KK : . . . . Wed, May 15, 5:53PM PDT (-0700 GMT). . . [459 ]
Yvonne- did ya get that line '442' ..?

jeff bourdeau : . . . . Wed, May 15, 5:53PM PDT (-0700 GMT). . . [460 ]
completed that is, that the orb

Chris, moderator : . . . . Wed, May 15, 5:53PM PDT (-0700 GMT). . . [461 ]
Those of you using America OnLine's web browser may or may not be able to
post to this chat server. If not, we apologize for the inconvenience.

Spider...High School Drop-Out : . . . . Wed, May 15, 5:53PM PDT (-0700 GMT).
. . [462 ]
Jeff...why would something in space, like the core of Jupitor, get

Broadclyst,UK : . . . . Wed, May 15, 5:53PM PDT (-0700 GMT). . . [463 ]
If we lived on Jupiter (say) and sent the probe to Earth - how much would we
have found out about the Earth? (for Chris Hunneyball)

Jeff Cuzzi, NASA : . . . . Wed, May 15, 5:54PM PDT (-0700 GMT). . . [464 ]
spider - message truncated...

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 5:54PM
PDT (-0700 GMT). . . [465 ]
Spider: We think that at the very center of Jupiter there is a rocky core,
about 5 Earth masses or so. Surrounding that there is a thick layer of
liquid metallic hydrogen. This is a form of hydrogen that occurs at very
high pressures and temperatures. The interesting thing is that it is
electrically conducting, so that is where Jupiter's magnetic field is
generated.

Marcie Smith, Probe Manager : . . . . Wed, May 15, 5:55PM PDT (-0700 GMT). .
. [466 ]
Oliver, We had Analogue Resistance Ablation detectors built into the heat
shield. These effectively measure the thickness of the heat shield as a
function of time. There were 10 sensors distributed in radius and length
along the probe. These are being used to measure the mass loss during entry.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 5:55PM PDT (-0700
GMT). . . [467 ]
Oliver, we had sensors imbedded in the heatshield to measure its thickness.
We recorded this data and knowing how the thickness changed, we can
calculate the mass loss.

Billy Biggs, student : . . . . Wed, May 15, 5:55PM PDT (-0700 GMT). . . [468
]
So, anybody want to comment on the similarities between the atmosphere of
Jupiter to that of other gas giants, and then to the sun (besides the H/He %
correlation)?

KK : . . . . Wed, May 15, 5:55PM PDT (-0700 GMT). . . [469 ]
Charlie- Thanks! .. An a mighty cool picture it is! Pun intended. ;)

Dennis Ting, programmer : . . . . Wed, May 15, 5:55PM PDT (-0700 GMT). . .
[470 ]
Monika, I want to thank you for allowing me to chat amongst some of your
colleagues. It's late here for us in the east coast. I am still at work.
(almost 9PM) I am constructing a web page. I'll let you know when it's
ready!! Charlie, Rich and all at NASA thank you very much for your time,
patience and hospitality. Let me know when another chat session rolls
around. Congratulations to the Galileo team on a job well done!

Justin - A 15 year old space fanatic : . . . . Wed, May 15, 5:55PM PDT
(-0700 GMT). . . [471 ]
Are there plans for sessions similar to this one??

Broadclyst,UK : . . . . Wed, May 15, 5:55PM PDT (-0700 GMT). . . [472 ]
If someone went to Jupiter, would they be able to get out again? (for Gemma
Wayne, 8)

Spider...High School Drop-Out : . . . . Wed, May 15, 5:56PM PDT (-0700 GMT).
. . [473 ]
Jeff...how can dust turn into somet

Yvonne Pendleton Astrophysicist : . . . . Wed, May 15, 5:56PM PDT (-0700
GMT). . . [474 ]
CCnet- there nearest star is about 4 light years away, we can't travel
anywhere near the speed of light, and there isn't a good reason to send any
life form to a star that I can think of. So, I don't see sending life forms
on extra solar missions as a good thing to do.

: . . . . Wed, May 15, 5:56PM PDT (-0700 GMT). . . [475 ]
How long after The next Europa encounter will we get some photo's?

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 5:56PM
PDT (-0700 GMT). . . [476 ]
Dan: Since the probe is decending at about 200 knots in a high density
atmosphere, and the probe is "vented", it wouldn't surprise me if a
considerable amount of hot atmosphere circulated through the probe interior.
My nose always got cold in my motorcycle helmet (even with the visor sealed)
by this same process...

Billy Biggs, student : . . . . Wed, May 15, 5:56PM PDT (-0700 GMT). . . [477
]
Rich: Based on the size and strength of the magnetic field, can you estimate
the size of the core?

Spider...High School Drop-Out : . . . . Wed, May 15, 5:57PM PDT (-0700 GMT).
. . [478 ]
So

Moderator2 : . . . . Wed, May 15, 5:57PM PDT (-0700 GMT). . . [479 ]
There may be a slow down in answers because the pizza just got to our
trailer! Yummy!

Yvonne Pendleton Astrophysicist : . . . . Wed, May 15, 5:58PM PDT (-0700
GMT). . . [480 ]
K.K.: I got the question, but while I was trying to think of the answer,
Charlie popped up and took it. He and I used to play softball together on a
team called the Space Cadets, and I remember he used to save me then too!

: . . . . Wed, May 15, 5:58PM PDT (-0700 GMT). . . [481 ]
I personelly believe you people are giving to many Kudos to the people of
NASA They made errors in design, and now are making the best of a bad
situation. If they had planned better to start with the wouldnt have to be
heroic now.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 5:58PM PDT (-0700 GMT). . . [482 ]
Spider - your questions are getting chopped off...

KK : . . . . Wed, May 15, 5:58PM PDT (-0700 GMT). . . [483 ]
Who do I give an idea to on how to open the Main Antenna? I have an idea. I
think it might actually work.

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 5:59PM PDT (-0700 GMT). .
. [484 ]
The heat shield's recession (shape change) due to ablation could be
determined because sensors were embedded in the heat shield at various
locations. These were sampled at a high data rate during the entry pulse to
provide a subsequent recreation of the shape change (and hence mass loss)
vs. time.

Broadclyst,UK : . . . . Wed, May 15, 5:59PM PDT (-0700 GMT). . . [485 ]
If you had the technology of December 1995 back when you built the probe -
what would you have done differently? (for Doug Bates, aged 46 1/4)

Explorer : . . . . Wed, May 15, 5:59PM PDT (-0700 GMT). . . [486 ]
Yes, the Galileo JOI was exciting. But what a long wait ! 6 years. I think
when we get the images and spectra back from the satellites, we'll really
feel the wait was worth it. (Oh, and of course, pics of Jupiter, too !)

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 5:59PM PDT (-0700
GMT). . . [487 ]
KK What's your idea?

kant : . . . . Wed, May 15, 6:00PM PDT (-0700 GMT). . . [488 ]
RALPH WALDO EMERSON ADMONISHES US NOT TO LOOK AT NATURE TOO CLOSELY. DO YOU,
JUST YOU, NOT ALL YOU, GIVE UP A PORTION OF SPIRITUAL MAGIC WHEN YOU MOVE SO
DEEPLY INTO NATURE AND PEER THAT CLOSELY AT HER SECRETS?

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:00PM
PDT (-0700 GMT). . . [489 ]
Billy: Thats a very good question. I don' think we can do that because we
don't know enough about the processes that actually generater the fluid
motions in the metallic core which then generate the magnetic field. The
situation is similar to understanding how the Earth's magnetic field is
generated in the molten iron core. In the case of the Earth we know the size
of the core from earthquake studies.

Dave Allard : . . . . Wed, May 15, 6:01PM PDT (-0700 GMT). . . [490 ]
JPL has a FAQ filled with suggestions they have received about the main
antenna.

Perry Donham : . . . . Wed, May 15, 6:01PM PDT (-0700 GMT). . . [491 ]
Brown dwarfs are, what, 10 Jupiter masses? Is the feeling that Jupiter is an
underachieving BD?

Oliver : . . . . Wed, May 15, 6:01PM PDT (-0700 GMT). . . [492 ]
Marcie : Thanks. The performance of the probe as an entry vehicle really
impresses me. I can't help thinking of possible military usages : it's
almost a nuclear blast shield ! Don't misread me, I very much favor civilian
applications, like this wonderful probe. The warhead entry vehicles must be
very, very, jealous !

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:01PM PDT (-0700 GMT). . . [493 ]
kant - do you lose a sense of beuty in a rainbow when you understand
refraction?

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 6:01PM PDT
(-0700 GMT). . . [494 ]
How about an online brainstorming session on unsticking the main antenna.
Who knows, we might come up with something useful. I'll go first. Carefully
create a flat spin to cause enough g-force to jolt the antenna without
breaking something else. Set up a program to stop the spin and re-orient the
craft automatically. (Risky, I know)

Monika Kress, astrophysics PhD student : . . . . Wed, May 15, 6:02PM PDT
(-0700 GMT). . . [495 ]
Hi folks.. I'm back. technical difficulties.....

KK : . . . . Wed, May 15, 6:02PM PDT (-0700 GMT). . . [496 ]
Eat your pizza. :) Respond to my Question 2 ( 483 ) when ya can :))

Explorer : . . . . Wed, May 15, 6:02PM PDT (-0700 GMT). . . [497 ]
Yeah, the stuck antenna was a poor design. But other missions have had
problems (like voyager's stuck scan platform) and come out alright in the
end. (However, such a low data rate is a worse problem than a scan platform
that had to be swivelled a bit !)

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:02PM PDT (-0700 GMT). .
. [498 ]
Steve, actually Jupiter's atmosphere is low density, when you consider that
the mass ratio of nitrogen (earth) to helium (jupiter) is 15:1 It's possible
that the gas entered through the aft vent and exited through the aerofairing
seams. But this is all conjecture.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:02PM PDT (-0700
GMT). . . [499 ]
Trevor, been there, done that.

Billy Biggs, student : . . . . Wed, May 15, 6:03PM PDT (-0700 GMT). . . [500
]
Were any discoveries made as to the movements of gases in the Jupiter
atmosphere?

: . . . . Wed, May 15, 6:03PM PDT (-0700 GMT). . . [501 ]
Iknow that the probe has trouble transmiting due to the dish not opening,
but does that effect recieving data from earth?

Justin - A 15 year old space fanatic : . . . . Wed, May 15, 6:04PM PDT
(-0700 GMT). . . [502 ]
Well I unfortently must be going. Great job with the mission so far I will
as always contiue to follow. Hope to see more sessions like this one!!
Congrats on you success thus far!!!

Explorer : . . . . Wed, May 15, 6:04PM PDT (-0700 GMT). . . [503 ]
kant, peering into nature always makes it more mystical than it was before
!!

: . . . . make progress. I know I love to see my own kids learn new things..
. . [504 ]

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:04PM
PDT (-0700 GMT). . . [504 ]
Billy: We measured winds of over 400 miles per hour.

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:04PM
PDT (-0700 GMT). . . [505 ]
KK: Send your idea to me by email. We can talk about it a bit and if it has
merit, I will share it with the fellow who is the antenna lead. Realize
though, that a lot of smart folks with intimate knowledge of the antenna
have been working on the problem for a long time without success...

Monika Kress, astrophysics PhD student : . . . . Wed, May 15, 6:04PM PDT
(-0700 GMT). . . [506 ]
KK... did I miss a question you asked me? I really did get booted off this
computer for a couple of minutes... in addition to having some pizza!

Marcie Smith, Probe Manager : . . . . Wed, May 15, 6:05PM PDT (-0700 GMT). .
. [507 ]
To whoever asked about the problem in sending commands to Galileo (put a
name in so we can answer you better!) -- the uplink has been affected in
that we have to use more power to transmit. But fortunately, on Earth, we
have the option to do that, on the spacecraft it has a limited amount of
transmit power and so we can't just increase the power.

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:06PM PDT (-0700 GMT). .
. [508 ]
Oliver, FYI the Probe's design utilized key technologies developed by the
nuclear industry. In fact, that's why GE was selected as the deceleration
module (heatshield) subcontractor: they had extensive experience designing
and building heat shields for nuclear warhead reentry vehicles.

Billy Biggs, student : . . . . Wed, May 15, 6:06PM PDT (-0700 GMT). . . [509
]
Rich: What effects wind speed and motion?

KK : . . . . Wed, May 15, 6:06PM PDT (-0700 GMT). . . [510 ]
Charlie- Can you turn the probe's Main Antenna into the direction the probe
is moving? I.E., 'stright ahead' ...? do yo see what I'm suggesting..? :)

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:07PM PDT (-0700
GMT). . . [511 ]
KK, I see what you're saying, but the space craft is in a vacuum... no wind.

Joe student : . . . . Wed, May 15, 6:08PM PDT (-0700 GMT). . . [512 ]
When will the first pictures of the ring system appear?

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:08PM PDT (-0700 GMT). .
. [513 ]
KK- a semantical point: "Probe" refers to the atmospheric entry vehicle;
"Orbiter" the spacecraft which flew overhead. The Probe's antenna was fixed
on top of its aft compartment.

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:09PM
PDT (-0700 GMT). . . [514 ]
Billy: When the atmosphere is heated by whatever manner, it produces
pressure variations, and the atmosphere is pushed from high pressure to low
pressure usually. Unless you are on a rapidly rotationg planet like Jupiter.
Then it gets more comlicated, but it is still bascially pressure gradients
that drive winds.

Dennis, space fan : . . . . Wed, May 15, 6:09PM PDT (-0700 GMT). . . [515 ]
Steve: With the knowledge gained on this mission, what have we learned about
Jupiter's age in relation to the other planets in our system? Do you think
that the system evolved as a whole?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:09PM PDT (-0700 GMT). . . [516 ]
Joe student - I'm not sure exactly, but maybe this summer some time..

TJ, teacher : . . . . Wed, May 15, 6:10PM PDT (-0700 GMT). . . [517 ]
Anyone - Am I correct that if the probe had been able to take images, some
of those images would have been of "clear" sky on the way down (i.e., places
with no clouds)?

Yvonne Pendleton Astrophysicist : . . . . Wed, May 15, 6:10PM PDT (-0700
GMT). . . [518 ]
Dennis, we still think that all the planets formed at roughly the same time.

Oliver : . . . . Wed, May 15, 6:10PM PDT (-0700 GMT). . . [519 ]
Dan: Thanks. This GE experience has been well used. I felt a general
similarity between the probe and RVs, now it's confirmed ! Is there any
classified technology in the probe ?

Noring, Student at Linkšping Institute of Technology, Sweden : . . . . Wed,
May 15, 6:10PM PDT (-0700 GMT). . . [520 ]
Dan Carlock, sorry for interrupting your dinner :) Do you know if there are
any online documents regarding the probe's computer systems?

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:11PM PDT (-0700 GMT). .
. [521 ]
TJ--- Yes.

Bart : . . . . Wed, May 15, 6:11PM PDT (-0700 GMT). . . [522 ]
Prope Scientist: When you were growing up did you ever dream of doing THIS?
What kind of music do probe scientists listen to?

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:11PM
PDT (-0700 GMT). . . [523 ]
The uplink to the spacecraft carries far less data than the downlink and we
can use very high power transmitters sitting on the ground, so the antenna
problem hasn't affected our ability to send commands up to the spacecraft
very much.

KK : . . . . Wed, May 15, 6:11PM PDT (-0700 GMT). . . [524 ]
Charlie- Yes, I realize that, but I was curious about when the probe's orbit
gets close to jupiter (or Europa), he speed of the probe, ANY infitesmally
small dust particulates, ...... any chance at all .....?

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:12PM
PDT (-0700 GMT). . . [525 ]
TJ, teacher: Yes there would likely have been clear sky, or maybe a thin
haze. On the next mission, Cassini, to Saturn there will be a camera to take
pictures on the probe into Titan's atmosphere.

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:13PM PDT (-0700 GMT). .
. [526 ]
Noring, no problem. (no food here anyway; I'm at work!) I'll email you what
I've got. Beyond that, perhaps the semiconductor industry has some on-line
spec sheets you could trawl for...

KK : . . . . Wed, May 15, 6:13PM PDT (-0700 GMT). . . [527 ]
Charlie- Yes, I realize that, but I was curious about when the probe's orbit
gets close to jupiter (or Europa), he speed of the probe, ANY infitesmally
small dust particulates, ...... any chance at all .....?

Joe student : . . . . Wed, May 15, 6:14PM PDT (-0700 GMT). . . [528 ]
since the probe is in orbit around jupiter, can it provide a gravity map of
jupiiter? I assume that the center of mass is located at the center of
Jupiter,but one never knows.Since jupiter rotates so fast one could get 20
or so rotations when the probe is near perigee.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:14PM PDT (-0700
GMT). . . [529 ]
KK, the short answer is "'fraid not". This idea was identified when we flew
very close to the Earth in 1992. It doesn't work.

Dennis, space fan : . . . . Wed, May 15, 6:14PM PDT (-0700 GMT). . . [530 ]
Steve: With the knowledge gained on this mission, what have we learned about
Jupiter's age in relation to the other planets in our system? Do you think
that the system evolved as a whole?

Billy Biggs, student : . . . . Wed, May 15, 6:15PM PDT (-0700 GMT). . . [531
]
What percentage of the composition is still unknown? If the probe entered in
a relatively empty part of Jupiter's atmosphere, are we still in the dark?

: . . . . Wed, May 15, 6:15PM PDT (-0700 GMT). . . [532 ]
RV 's ? Recreational vehicles ??

Marcie Smith, Probe Manager : . . . . Wed, May 15, 6:15PM PDT (-0700 GMT). .
. [533 ]
Joe student, the radio link will be used to update the gravity map of
Jupiter. The map will be much better from the Orbiter with 2 years of data
than from the flybys we had with previous spacecraft.

KK : . . . . Wed, May 15, 6:15PM PDT (-0700 GMT). . . [534 ]
Whoop. My mistake.. I mean "Orbiter" any time I said 'probe'

Broadclyst,UK : . . . . Wed, May 15, 6:16PM PDT (-0700 GMT). . . [535 ]
As a 'Neighbourhood Engineer' (a voluntary arrangement in the UK where
professsional engineers assist in schools) we have an annual 'N/Es Challenge
Day' for students age 12-13 yrs. Do _you_ have a good challenge for _them_
to do this year in June? (Doug)

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 6:16PM PDT
(-0700 GMT). . . [536 ]
What kinds of things will you be looking for on Europa to indicate the
exciting possibility of oceans of water beneath the ice crust? Is there any
way of estimating the temp. of this water then?

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:16PM
PDT (-0700 GMT). . . [537 ]
Bart: I have to admit I never dreamed I would be doing this, but what a
great experience! I like new age music most I think.

Yvonne Pendleton Astrophysicist : . . . . Wed, May 15, 6:16PM PDT (-0700
GMT). . . [538 ]
I have to go now, but I really enjoyed chatting with you all. Please check
out my web site at www-space.arc.nasa.gov/~stardust K.K.- I think Charlie
gave the best answer for question 442. Bye now!

Oliver : . . . . Wed, May 15, 6:17PM PDT (-0700 GMT). . . [539 ]
Trajectory Question : after seeing those highly eccentric orbits, I couldn't
help thinking : couldte Orbiter have a look at some of the outermost moons ?
(say, in an extended mission ...)

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:17PM PDT (-0700 GMT). . . [540 ]
Trevor - there will be more than one opportunity to look for "new" surface
features; also the Infrared telescope can look for local "warm spots".

: . . . . Wed, May 15, 6:18PM PDT (-0700 GMT). . . [541 ]
What is likely to happen to all the Galileo people in 2 years, when the
primary mission is over ? Can they go to pther projects or will there be a
surplus of people and no jobs for them ? (hope all that expertise is not
lost !)

Jane Rigby, entering freshman (astrophysics) at Penn State : . . . . Wed,
May 15, 6:18PM PDT (-0700 GMT). . . [542 ]
Goodbye Yvonne! Thank you for all your help!

KK : . . . . Wed, May 15, 6:18PM PDT (-0700 GMT). . . [543 ]
Charlie- Oh. So it's been thought of already, 6 years ago. Dang. :)

: . . . . Wed, May 15, 6:19PM PDT (-0700 GMT). . . [544 ]
yes, what about those other mooons ??] will any pictures be taken of
Amalthea, or other moons not even mentioned by any Galileo people up to now
?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:19PM PDT (-0700
GMT). . . [545 ]
Oliver, I'm sure the orbiter will look at anything it has an opportunity to!
But it is specifically targetted for the Galilean satellites, partly because
it needs the gravity assist on each orbit to kick it into the next.

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:19PM PDT (-0700 GMT). .
. [546 ]
Folks have been and are continuing to leave the Project to transition to new
assignments. Speaking for myself, I will probably leave by September of this
year.

Billy Biggs, student : . . . . Wed, May 15, 6:19PM PDT (-0700 GMT). . . [547
]
Could somebody clarify some info I have from one of the press releases. Is
there any liquid in the Jovian atmosphere?

Broadclyst,UK : . . . . Wed, May 15, 6:20PM PDT (-0700 GMT). . . [548 ]
Can we see the CVs of your panel, to give some insight into the skills and
experience students need to aspire to? (Doug)

KK : . . . . Wed, May 15, 6:20PM PDT (-0700 GMT). . . [549 ]
Yvonne- Thanks! Take care :)

kant : . . . . Wed, May 15, 6:20PM PDT (-0700 GMT). . . [550 ]
WELL ANSWERED, JEFF. I HAVE FELT MY PULSE RACE LOOKING AT SOME OF THE DEEP
SPACE SHOTS FROM HUBBLE. IF IT WERE NOT IMPOSSIBLE TO MAINTAIN A HOAX ON
THAT SCALE I WOULD DOUBT THE REALITY OF SOME OF THE IMAGES.

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:20PM
PDT (-0700 GMT). . . [551 ]
Joe student: Great Question! Rich, has anyone looked at how the grav
potential varies from a simple oblate model? The orbits of the moons could
probably see these effects as well. Could, for example upwelling in certain
latitude bands keep the atmosphere from achieving isostatic equilibrum?

: . . . . Wed, May 15, 6:21PM PDT (-0700 GMT). . . [552 ]
Thanks for taking us back to Jupiter, Galileo team ! Please post this chat.
Bye...

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:21PM
PDT (-0700 GMT). . . [553 ]
Billy: We think that there might be some possiblilty that composition could
vary with position on Jupiter to some extent. With only one probe there is
always a problem on how to know how typical the measurements are. But we
think we have learned a great deal about Jupiter with the Galileo probe and
most of the composition results are probably tupical of the whole planet.

Joe student : . . . . Wed, May 15, 6:21PM PDT (-0700 GMT). . . [554 ]
Will image compression be used on all deep space probes from now on?(ex.)
cassini,mARS

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:22PM PDT (-0700
GMT). . . [555 ]
Galileo engineers and mission support people are transitioning to other
projects all the time. Many of us are working on several projects at the
same time. New projects are always in need of knowledgeable, experience
people, and the value we can bring in terms of lessons learned are
important.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:22PM PDT (-0700 GMT). . . [556 ]
... all the major moons, such as Callisto, Ganymede, Europa, and Io, as well
as MAYBE some of the smaller ones like Amalthea. Too bad, though, we lost
the best closeups of Io which were scheduled for the inbound pass when the
tape recorder was dicy.

KK : . . . . Wed, May 15, 6:23PM PDT (-0700 GMT). . . [557 ]
How much of an 'Oblate Spheriod' IS jupiter, btw?

Billy Biggs, student : . . . . Wed, May 15, 6:24PM PDT (-0700 GMT). . . [558
]
Something I'm unsure of here, is Galileo the only probe to directly examine
Jupiter (besides Voyager, I guess?)?

Jane Rigby, entering freshman (astrophysics) at Penn State : . . . . Wed,
May 15, 6:24PM PDT (-0700 GMT). . . [559 ]
Thank you everyone! This has been both fascinating and informative. If
anyone wishes to contact me further, I'm at jrigby@udel.edu. Again, thanks
all!

Broadclyst,UK : . . . . Wed, May 15, 6:24PM PDT (-0700 GMT). . . [560 ]
(of image compression) How will you know that subtle artifacts seen are not
an aberation of the compression (viz JPEG)? - Doug

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:25PM PDT (-0700 GMT). . . [561 ]
KANT - I AGREE. TRUTH IS STRANGER THAN FICTION, THEY SAY, AND I HAVE FOUND
THAT REALITY IS A LOT MORE CREATIVE THAN OUR IMAGINATIONS (BEING PRIMARILY A
THEORIST MYSELF).

Bart : . . . . Wed, May 15, 6:25PM PDT (-0700 GMT). . . [562 ]
Probe Scientist...when you do experiments in a lab, you always use a
"control" (to see it everything is working correctly), was their a "control"
on the probe?

TJ, teacher : . . . . Wed, May 15, 6:25PM PDT (-0700 GMT). . . [563 ]
Dan Carlock and Rich Young - Re: clear areas in atmosphere, that's neat
because I think the average person pictures Jupiter's atmosphere as being
completely opaque at all levels

KK : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). . . [564 ]
Doug has a good question. ( 560 )

Karen, moderator : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). . . [565 ]
Doug, you can see the profiles of many of the panel participants at
http:/quest.arc.nasa.gov/jupiter.html (follow the "People" link).

Joe student : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). . . [566 ]
The gravity map would be very crude due to all extra masses
around(moons,ring system,dust, and the is not very good for a graivity study
because of it being elongated.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). . . [567 ]
JOE STUDENT - IMAGE COMPRESSION WILL BE USED ON CASSINI; it is in two sorts
- 2X "lossless" compression which retains all the image information and up
to 40x (!!) "lossy" compression that loses some information on brightness
levels.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:26PM PDT (-0700
GMT). . . [568 ]
Billy, the Pioneer 10 and 11 spacecraft, as well as Voyagers 1 and 2 flew
past Jupiter and made measurements. The Galileo Orbiter will be the first
spacecraft to stay in orbit and get a long look, and the Galileo probe was
the only spacecraft to actually enter the atmosphere to take direct
measurement.

Broadclyst,UK : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). . . [569 ]
If you had the technology of December 1995 back when you built the probe -
what would you have done differently? (for Doug Bates, aged 46 1/4)

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:26PM PDT (-0700 GMT). .
. [570 ]
KK, I believe that the flattening factor = 0.065 for Jupiter. This defines
the oblate spheroid

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:27PM
PDT (-0700 GMT). . . [571 ]
Joe student: as flight computers get faster and more capable, there is no
reason not to include image compression of some kind on future missions.
There is a trade off though, any form of compression is based on some
assumptions about the data you are compressing. We don't want to make too
many assumptions or we will filter out all the "surprises" that make the
exploring fun...

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:27PM PDT (-0700 GMT). . . [572 ]
Steve Collins - hey, are you the same as Andy Collins?

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:28PM
PDT (-0700 GMT). . . [573 ]
Steve: Yes, they have done rather detailed models accounting for the effects
of rotation on the gravity field. The orbits of the moons could be affected
by oblateness of Jupiter, but the oblateness effects fall off rapidly with
distance form Jupiter. Yes, it should be possible for upwelling atmosphere
to cause significant deviation from isostacy, depending on the speed of the
updrafts.

Joe student : . . . . Wed, May 15, 6:28PM PDT (-0700 GMT). . . [574 ]
Whoops "the orbit is not very good"

KK : . . . . Wed, May 15, 6:28PM PDT (-0700 GMT). . . [575 ]
TJ- have you looked at the INFARED photos? Very 'opaque' :)

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 6:28PM PDT
(-0700 GMT). . . [576 ]
I read somewhere once, of some far-fetched ideas of sending highly trained,
but expendable dolphin astronauts to Europa. The plan was to drill through
the ice crust and send them in with instrument back-packs,(and a modified
environmental suit of course) to gather and return information. Pretty
sci-fi, I agree, but wouldn't it be feasable one day with the equivalent of
some of our deep sea remote probes? That would satisfy the Animal rights
people anyway:)

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:30PM
PDT (-0700 GMT). . . [577 ]
Bart: Most of the instruments had calibration background measurements that
they used to make sure the instrument wasn't drifting away from where it
should be.

KK : . . . . Wed, May 15, 6:30PM PDT (-0700 GMT). . . [578 ]
oop. I mean 'clear', TJ. Can I blame my misspelling on 'line noise' ..? ;^]

Billy Biggs, student : . . . . Wed, May 15, 6:30PM PDT (-0700 GMT). . . [579
]
Based on results from this probe, are gas giants in general more likely to
be more closely related to stars then planets?

Magalhaes Planetary Scientist : . . . . Wed, May 15, 6:30PM PDT (-0700 GMT).
. . [580 ]
Julio Magalh‹es. HI! I am part of the Galileo Probe Team and am a specialist
in the study of winds in planetary atmospheres. My principal role on the
Galileo Probe Team is a a coordinator for educational outreach.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:30PM PDT (-0700
GMT). . . [581 ]
Doug, with new technology, everything would use microprocessors, giving us a
lot more flexibility. The instruments would probably do more onboard data
processing, reducing the bit rates needed to bring down the scientific
results, or alternatively, increasing the results you could bring down at a
given bit rate...

Oliver : . . . . Wed, May 15, 6:31PM PDT (-0700 GMT). . . [582 ]
Stupid question : with those new measurements on the upper atmosphere, could
a future, more massive orbiter just be aerobraked ?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:31PM PDT (-0700 GMT). . . [583 ]

Pete : . . . . Wed, May 15, 6:31PM PDT (-0700 GMT). . . [584 ]
Why is there a two year limit on Galileo's research? What willoccur to
"stop" the program? Will Galileo's orbit decay?

Tom Ford, physics teacher : . . . . Wed, May 15, 6:31PM PDT (-0700 GMT). . .
[585 ]
How was the probe mass lost during entry determined? What and where was the
instrumentation?

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:31PM
PDT (-0700 GMT). . . [586 ]
Jeff: Different. Andy and I have taken different first names in a futile
effort to distinguish ourselves

Bob Cameron VE9MSC Maclean Space Centre : . . . . Wed, May 15, 6:31PM PDT
(-0700 GMT). . . [587 ]
Nice to see all the interest we have viewed the pass progress of voyager and
pioneer projects through slow scan TV on amateur radio this net allows more
interaction congratulations. t

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:32PM PDT (-0700 GMT). . . [588 ]
Oliver - not stupid at all. We are right now designing an orbiter for
Neptune that would be aerocaptured. Also, there are several Mars orbiter
missions that will use some aerobraking.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:32PM PDT (-0700 GMT). . . [589 ]
Steve - Even more confusing because as I recall Andy's original name was
Steve - right? Did you two flip a coin or what?

Billy Biggs, student : . . . . Wed, May 15, 6:33PM PDT (-0700 GMT). . . [590
]
Magalhaes: Can you give any interpretation of the results from the probe in
regards to Jovian winds?

Moderator2 : . . . . Wed, May 15, 6:33PM PDT (-0700 GMT). . . [591 ]
To Tom Ford - that was answered earlier. Sensors in the` heat shield
monitored it's ablation during descent at a fast data rate.

Broadclyst,UK : . . . . Wed, May 15, 6:34PM PDT (-0700 GMT). . . [592 ]
(To Charlie ]with new technology, everything would use microprocessors) Do
you mean the electronics are discrete components - I thought they invented
chip to go to the moon? (Doug)

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:34PM PDT (-0700
GMT). . . [593 ]
Oliver, aerobraking is an area getting a lot of attention these days. But it
is had to test out in many cases. The atmosperic probe essentually used
aerobraking, but of course the tough part is not simply to enter, but to
simply slow down and go into orbit...

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:34PM
PDT (-0700 GMT). . . [594 ]
Billy: The gas giants are more closely related to planets, because they do
not convert hydrogen into helium to produce energy. But there is the
question of whether they formed more like the sun rather than like the inner
planets,like Earth. It now looks like Jupiter probably formed more like the
Earth, because of the enrichment of carbon and nitrogen over solar
abundance. But that interpretation might change later with more analysis.

TJ, teacher : . . . . Wed, May 15, 6:35PM PDT (-0700 GMT). . . [595 ]
Will any of the Galileo probe's experience translate into design changes in
the Cassini probe, or is that project too far along for any changes?

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:35PM PDT (-0700 GMT). .
. [596 ]
Tom Ford, the Probe used electrical resistance detectors imbedded into the
heat shield. Please scroll back to find more detailed responses.

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:35PM
PDT (-0700 GMT). . . [597 ]
Rich: I've read that Jupiter's Neon abundance is lots higher than solar.
What is that telling us?

Joe student : . . . . Wed, May 15, 6:36PM PDT (-0700 GMT). . . [598 ]
How do you plan on aerocapture working on neptune?we know so little about
it? (ex. Mass, atmosphereic density)

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:36PM PDT (-0700 GMT). . . [599 ]
TJ, teacher - The probe is being built by the European Space Agency, and it
is pretty well along. Remember that it is rather a different entry problem
(Titan has much lower gravity so the entry velocity is much lower).

Rich Young, Galileo Probe Project Scientist : . . . . Wed, May 15, 6:36PM
PDT (-0700 GMT). . . [600 ]
TO all: Thanks for all your questions. I am signing off now. But keep it up,
there are other folks taking over.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:36PM PDT (-0700
GMT). . . [601 ]
Doug, the Appolo program resulted in transistors, not true microprocessors.
Processors have been around for a long time, but remember, the Galileo
spacecraft used 1975 vintage parts, and they needed to be radiation
hardened. Not many advanced processor fit the bill at that time.

Broadclyst,UK : . . . . Wed, May 15, 6:36PM PDT (-0700 GMT). . . [602 ]
As a 'Neighbourhood Engineer' (a voluntary arrangement in the UK where
professsional engineers assist in schools) we have an annual 'N/Es Challenge
Day' for students age 12-13 yrs. Do _you_ have a good challenge for _them_
to do this year in June? (Doug)

Bob Cameron VE9MSC Maclean Space Centre : . . . . Wed, May 15, 6:37PM PDT
(-0700 GMT). . . [603 ]
Nice to see all the interest we have viewed the pass progress of voyager and
pioneer projects through slow scan TV on amateur radio this net allows more
interaction congratulations. t

pete (mech eng grad student) : . . . . Wed, May 15, 6:38PM PDT (-0700 GMT).
. . [604 ]
hey panellists, thanks for all your time tonight. congratulations on such
success after so many years' work. it's been great (and inspiring) to have
so much info on the WWW and such about how the mission has operated.
G'night.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:38PM PDT (-0700 GMT). . . [605 ]
Joe Student - well, we did have the voyager flyby. Of course there will be
an uncertainty envelope to deal with. Maybe we will make it a "smart" probe.

Dan Carlock, Probe Engineer : . . . . Wed, May 15, 6:38PM PDT (-0700 GMT). .
. [606 ]
It's time for me to sign off, too. I have really enjoyed answering your
questions. Hooray for Galileo Probe!!!

KK : . . . . Wed, May 15, 6:38PM PDT (-0700 GMT). . . [607 ]
BTW NASA folks- This is very cool. And yes, I continually E-Mail my
respective Honerable Senators to Heavily Fund and Generally Be Nice Dollar
Wise. NASA is IT. :))

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 6:38PM PDT (-0700
GMT). . . [608 ]
Hi, I'm Richard Gerber. I'm an astrophysicist working at NASA Ames Research
center. I'm not directly involved with the Galileo Probe, but I'm looking
forward to answering any questions I can. In addition, I'd looking forward
to finding out what you are interested in learning about Jupiter and the
solar system. So far, I've been very impressed with the questions!

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:38PM PDT (-0700
GMT). . . [609 ]
TJ, we recently spoke with the Cassini/Huygens probe designers about the
problems we had with Galileo. At this time they do not appear to be
susceptable to the same problems, but we will continue to keep in touch with
them.

Billy Biggs, student : . . . . Wed, May 15, 6:38PM PDT (-0700 GMT). . . [610
]
Rich: Thank you for your time and answers.

Oliver : . . . . Wed, May 15, 6:39PM PDT (-0700 GMT). . . [611 ]
Jeff : this Neptune orbiter is one of the most exciting things I've heard
lately ! Now if there's some kind of mission profile summary somewhere on
the web ? The reason why I said my question was perhaps stupid is that I
don't know the ratio between the weight of an aerobrake and the weight of
the fuel+engine it replaces, so I had my doubts for light spacecraft.

mike from PA : . . . . Wed, May 15, 6:39PM PDT (-0700 GMT). . . [612 ]
why did you send a probe to jupiter?

kant : . . . . Wed, May 15, 6:40PM PDT (-0700 GMT). . . [613 ]
THANKS FOR THE REPONSE, JEFF.

Joe student : . . . . Wed, May 15, 6:40PM PDT (-0700 GMT). . . [614 ]
How certain were you guys that the probe was going to survive entry into
jupiter?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:40PM PDT (-0700 GMT). . . [615 ]
Steve - Rich told me the Neon is actually very low (0.1 solar) and is
thought to be carried down to the core with the Helium. Other rare gases are
elevated, as "expected".

Magalhaes Planetary Scientist : . . . . Wed, May 15, 6:41PM PDT (-0700 GMT).
. . [616 ]
Billy Biggs: Answer to wind result interpretation.... The continued strength
of the winds until the end of the probe mission is a major result. This
result clearly shows that the winds are not restricted to a shallow layer of
strong winds. Some scientists interpret this result to mean the winds must
be generated by Jupiter's internal heat percolating up from Jupiter's
depths. Others (such as myself) feel this implication is not entirely clear.
Producing winds via heating by sunlight is not entirely exclueded in my
opinion.

Pete : . . . . Wed, May 15, 6:42PM PDT (-0700 GMT). . . [617 ]
To Richard Gerber, could you tell me what will happen to Galileo in two
yaers that will "end" it's research . . .will it's orbit decay?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:42PM PDT (-0700
GMT). . . [618 ]
Joe S., I, for one was quite certain it would survive ( a lot of very
talented people worked long and hard to assure this). I didn't lose a wink
of sleep. But once we learned that it had worked, all these same people let
out one VERY long sigh!

Galileo Orbiter AACS Backroom (Steve Collins) : . . . . Wed, May 15, 6:42PM
PDT (-0700 GMT). . . [619 ]
Steve Collins (orbiter engineering team AACS) here, I need to split for home
at this point. I will try to rejoing in a short while from there...

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:42PM PDT (-0700 GMT). . . [620 ]
Oliver - the trade is very clear - you win big time with aerocapture, if it
can be done. As you said, it is tricky with the uncertainties and all, so
needs to be studied carefully. I don't think it has progressed to the point
of a web page yet though.

Billy Biggs, student : . . . . Wed, May 15, 6:42PM PDT (-0700 GMT). . . [621
]
Jeff: Any ideas as to what chemical reactions commonly occur in the
atmosphere of Jupiter?

Tom Ford, physics teacher : . . . . Wed, May 15, 6:43PM PDT (-0700 GMT). . .
[622 ]
How was the probe mass lost during entry determined? What and where was the
instrumentation?

Pete : . . . . Wed, May 15, 6:43PM PDT (-0700 GMT). . . [623 ]
To Richard Gerber: could you tell me what will happen to Galileo in two
years that will "end" it's research . . .will it's orbit decay?

Joe student : . . . . Wed, May 15, 6:43PM PDT (-0700 GMT). . . [624 ]
Will you guys ever design another orbiter with a dish that will unfurl? I
noticed that Cassini has a fixed dish, is this due to the problem Galieo
Has?

Jake, Amateur Engineer : . . . . Wed, May 15, 6:44PM PDT (-0700 GMT). . .
[625 ]
Two questions. One: How many compressed, black & white images can the much
maligned tape-recorder now hold? Second: What will be the Ganymede flyby
velocity for Galileo relative to Jupiter; and compare it to the jovian
escape velocity at the Ganymede orbital distance?

Oliver : . . . . Wed, May 15, 6:44PM PDT (-0700 GMT). . . [626 ]
Richard, the Astrophysicist : Hello. One of my questions (Marcie didn't have
the data handy at the time) was : where in the Jovian system do you find a
radiation level compatible with manned exploration ? One of my "fears" was
that maybe the 4 galileans were in belt where you'd get lethal doses.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:44PM PDT (-0700 GMT). . . [627 ]
Billy - well, I think most of the ongoing chemistry is photochemical. That
is, like the LA smog. Creating ethane, etc, from Methane. There was some
interesting chemistry that occurred in the impact by Comet Shoemaker-Levy
and in a few minutes we will have a real expert on that joining us - Kevin
Zahnle.

Billy Biggs, student : . . . . Wed, May 15, 6:45PM PDT (-0700 GMT). . . [628
]
Magalhaes: Do the winds occur in layers? Also, does the radiation belt or
the magnetic field have any effect on the winds?

KK : . . . . Wed, May 15, 6:45PM PDT (-0700 GMT). . . [629 ]
Richard Gerber- Do you know if the DC-X (Douglas version Clipper Ship 333)
is capable of launching Galileo -type probes...?

Kevin Zahnle, NASA : . . . . Wed, May 15, 6:45PM PDT (-0700 GMT). . . [630 ]
Hi. I'm Thrak I'm a NASA Scientist! Ask me!

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:46PM PDT (-0700
GMT). . . [631 ]
Tom, There were resistive sensors imbedded in the probe's heatshield. The
signal we got from sensors indicated their length, and as the heatshield
burned away, the sensors got shorter and the signals got smaller. Based on
these signals, we know how the thickness of the heatshield varied during
deceleration, and we can calculate the mass loss.

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 6:46PM PDT
(-0700 GMT). . . [632 ]
I read that the dynamics which cause the high windspeeds on Jupiter were
found to be affected by thermal convection more than expected. Any new news
on this?

Pete : . . . . Wed, May 15, 6:46PM PDT (-0700 GMT). . . [633 ]
Hello Richard: Could you tell me what will happen to Galileo in two years?
Will it stop transmitting data? Will it's orbit decay?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:46PM PDT (-0700 GMT). . . [634 ]
Joe Student - yes, Cassini has a fixed antenna. I suspect we will be seeing
a lot of those for quite some time now.

Billy Biggs, student : . . . . Wed, May 15, 6:47PM PDT (-0700 GMT). . . [635
]
Kevin! While it's not the topic of discussion (directly), could you _please_
give me an overview of the chemistry involved in the Shoemaker-levy or any
atmospheric chemistry of Jupiter?? :)

Broadclyst,UK : . . . . Wed, May 15, 6:47PM PDT (-0700 GMT). . . [636 ]
Any engineers going to challenge our 12-13yr olds (Q535)

Metric A/S, Norway : . . . . Wed, May 15, 6:47PM PDT (-0700 GMT). . . [637 ]
How do you ensure that the very valuable knowledge of all the people, do not
dissapear, when the prodject is over. It is only the results from the
mission that are stored?

TJ, teacher : . . . . Wed, May 15, 6:47PM PDT (-0700 GMT). . . [638 ]
Is it fair to say that Jupiter's atmosphere appears to be much less
homogeneous than expected? If so, will some kind of "multi-probe" be the way
to answer many of the new questions raised by Galileo (if funding can be
generated, of course)?

Oliver : . . . . Wed, May 15, 6:48PM PDT (-0700 GMT). . . [639 ]
Jeff : Thanks. Don't worry to much for a web page ... Anyway, if you could
point out publications or reports re: 1/ aerobraking and 2/ neptune probes,
etc. I'd be grateful.

Jamie Cox : . . . . Wed, May 15, 6:48PM PDT (-0700 GMT). . . [640 ]
I am a software engineer working with embedded systems. How useful do you
find simulation? Do you have a Galileo-on-board-computer instruction set
simulator?

Billy Biggs, student : . . . . Wed, May 15, 6:48PM PDT (-0700 GMT). . . [641
]
(Just to explain my slant here, I'm researching a grade 12 chemistry project
on jupiter's atmosphere, specifically what what gained from the Galileo
probe.)

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 6:49PM PDT (-0700
GMT). . . [642 ]
Pete: The orbiter's life will "end" when it runs out of fuel. It's orbit may
eventually decay and/or it won't have fuel needed to aim its antenna toward
Earth.

Joe student : . . . . Wed, May 15, 6:50PM PDT (-0700 GMT). . . [643 ]
Will Galileo still be working when Cassini criuses on by? The reason I ask
is that it could act like a repeater for galileo. Receive data from galileo
at a fairly high data rate then Cassini could transmit that data to us.

Jamie Cox : . . . . Wed, May 15, 6:50PM PDT (-0700 GMT). . . [644 ]
I am a software engineer working with embedded systems. How useful do you
find simulation? Do you have a Galileo-on-board-computer instruction set
simulator?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:52PM PDT (-0700 GMT). . . [645 ]
Oliver - I will need to look into that one. Got an email or other address?

Kevin Zahnle, NASA : . . . . Wed, May 15, 6:52PM PDT (-0700 GMT). . . [646 ]
Howdy, Billy. Sure. Observed chemicals were mostly reduced compounds of
carbon and sulfur. The most interesting were S2, CS2, CS, OCS, CO, H2O,
HCN... All are products of chemical reactions in gases with more carbon than
oxygen, except for water.

KW Spaceteacher : . . . . Wed, May 15, 6:53PM PDT (-0700 GMT). . . [647 ]
With Jupiter emitting so much heat, and it's satellites having the
conditions making life possible, would it be possible to create life on
Earth in the way distant future? (Assuming that we are around.)

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:53PM PDT (-0700 GMT). . . [648 ]
Joe Student - Cassini will probably go by after Galileo "dies". Galileo runs
for about 2 years and Cassini goes by in the 2000 timeframe (I should know
the exact date but I don't). Cassini doesn't launch until Oct '97, and has
to go around Earth and Venus.

Oliver : . . . . Wed, May 15, 6:53PM PDT (-0700 GMT). . . [649 ]
Jeff : my email is devuns@thomsoft.com

Kevin Zahnle, NASA : . . . . Wed, May 15, 6:54PM PDT (-0700 GMT). . . [650 ]
The molecules with oxygen were made from mixed comet + Jupiter The molecules
without oxygen were probably purely from charred Jupiter.

Jamie Cox : . . . . Wed, May 15, 6:54PM PDT (-0700 GMT). . . [651 ]
I am a software engineer working with embedded systems. How useful do you
find simulation? Do you have a Galileo-on-board-computer instruction set
simulator?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:54PM PDT (-0700 GMT). . . [652 ]
KW Spaceteacher - come again?

KK : . . . . Wed, May 15, 6:55PM PDT (-0700 GMT). . . [653 ]
Richard Gerber- Is the Delta Clipper ( any of the 3 submittalls ) designed
or capable of handling a Galileo type spacecraft?

kant : . . . . Wed, May 15, 6:55PM PDT (-0700 GMT). . . [654 ]
GOOD NIGHT. GOOD LUCK. I SIMPLY CANNOT COMPREHEND HOW FAR 78 MILLION LIGHT
YEARS IS!!!

Jeff Hollingsworth, Mars Atmospheric Science (SJSUF/NASA Ames) : . . . .
Wed, May 15, 6:55PM PDT (-0700 GMT). . . [655 ]
Hi. I'm Jeff Hollingsworth. I'm a University Research Associate (SJSUF) in
residence at NASA Ames. Though I'm not directly involved with the Galileo
Project, I'd be more than happy to help field questions regarding
atmospheric science. My research background is in Mars meteorology and
climate modeling. I'm a member of NASA Ames' Mars Global Circulation
Modeling Group (button Be sure to check out the "Mars Room" in the WebChat
area.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:55PM PDT (-0700 GMT). . . [656 ]
Oliver - OK, I will see what I can come up with and get back to you.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:55PM PDT (-0700
GMT). . . [657 ]
Jamie, We have several Galileo spacecraft simulators of various degrees of
fidelity. The most accurate is what we call the testbed. It is essentially
an identical spacecraft built from spare parts. It resides at JPL and we use
it to test out command sequences etc. to ensure that they work before they
are uplinked to the spacecraft.

Billy Biggs, student : . . . . Wed, May 15, 6:55PM PDT (-0700 GMT). . . [658
]
Kevin: Can you give me a bit of an overview of what happend when the comet
hit and what you could extrapolate from observations of the impact (if
anything)?

Zuma's Electronic C@fe - NASA Seminar : . . . . Wed, May 15, 6:56PM PDT
(-0700 GMT). . . [659 ]
Whta kind of material was the Galileo's parachute made out of? Metallic?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 6:56PM PDT (-0700
GMT). . . [660 ]
Jamie: I'm not exactly sure what you are asking here. Do you mean: did
Galileo have some sort of "smart systems" software. I know there is an
effort here at Ames to produce intelligent spacecraft for future missions.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 6:56PM PDT (-0700 GMT). . . [661 ]
kant - 'night - none of us can either.

Magalhaes Planetary Scientist : . . . . Wed, May 15, 6:56PM PDT (-0700 GMT).
. . [662 ]
Broadclyst, UK: Your question on Neighborhood Engineer Challenge for
students. You might challenge the students to figure out how to find cloud
particles (or smoke) from a moving spacecraft without a camera. For example,
with their eyes closed they would have to find some way of figuring out if
they are in a cloud. Of course, smoke could be "smelled" etc, but how would
they determine if there is smoke if they did not have a sense of smell.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 6:57PM PDT (-0700
GMT). . . [663 ]
Zuma, the Galileo parachute was made of Dacron.

Broadclyst,UK : . . . . Wed, May 15, 6:57PM PDT (-0700 GMT). . . [664 ]
As a 'Neighbourhood Engineer' (a voluntary arrangement in the UK where
professsional engineers assist in schools) we have an annual 'N/Es Challenge
Day' for students age 12-13 yrs. Do _you_ have a good challenge for _them_
to do this year in June? (Doug) (Repeat Question - perhaps someone on your
team could Email me (Doug@Darkstar.zynet.co.uk) because I am sure the
students would appreciate subcontracting some of your problem solving. In
previous years we have done design/buildrace bottle boats, cars and tethered
planes, structures, package/drop testing raw eggs etc. etc.)

TJ, teacher : . . . . Wed, May 15, 6:58PM PDT (-0700 GMT). . . [665 ]
To everyone involved in the Galileo project, particularly those taking the
time to participate in this webchat, congratulations on a very successful
mission. Your work epitomizes good science, and you all make excellent role
models for today's students.

Billy Biggs, student : . . . . Wed, May 15, 6:59PM PDT (-0700 GMT). . . [666
]
Could someone please clarify the differences between what the heat of
Jupiter was estimated to be and what it was measured to be? Does the heat
level of Jupiter restrict the types of chemical reactions that occur in the
atmosphere?

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:00PM PDT (-0700 GMT). . . [667 ]
Broadclyst: Another possibility would be for the young engineers to design
all-terrain vehicles or "rovers" that could explore the surface of MArs,
maybe with "smart" sensors on board to avoid rocks, holes, etc. Wheels?
Legs? etc.

Kevin Zahnle, NASA : . . . . Wed, May 15, 7:00PM PDT (-0700 GMT). . . [668 ]
BB - ok, comet hits atmosphere, explodes. Explosion sends shocks through
air, comet. Explodes a hole in the atmosphere, stuff is ejected at high
velocity into near Jupiter space. Eventually stuff falls down again, 5-15
minutes later, and when it hits the atmosphere stuff gets hot again. When
jovian air is shocked, you get soot and other carbonaceous stuff. When the
comet gets shocked, you get all sorts of stuff, including gases like CO and
water, and probably lots of soot and rock dust and....

Jamie Cox : . . . . Wed, May 15, 7:00PM PDT (-0700 GMT). . . [669 ]
I was asking about what simulation tools you use on the ground to develop
software for Galileo. In particular, I am interested in software-only
simulation, in which software on a general-purpose computer simulates
hardware/software of the target system. (Can you test your Galileo SW on a
Sun, for example? Or, do you have to wait for time on a hardware test bed?)

Bruce P, Amature Astronomer : . . . . Wed, May 15, 7:00PM PDT (-0700 GMT). .
. [670 ]
Hello..I missed the earlier part of the discussion. Will the Galileo be
sending back any visual pictures we can see and if so will they be on the
web?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:00PM PDT (-0700
GMT). . . [671 ]
KK: I don't believe a Delta Clipper would be capable of launching a Galileo
Probe type mission. Future NASA missions will probably be smaller and
lighter, with the hope that there will be more of them.

Broadclyst,UK : . . . . Wed, May 15, 7:01PM PDT (-0700 GMT). . . [672 ]
(To Magalhaes) Thanks for that - you've got me worried now - in the past we
choose things _we_ knew how to do! ;-)

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:03PM PDT (-0700
GMT). . . [673 ]
Jamie, WE also have strictly software simulators, but their fidelity is less
good, and they catch fewer of the problems. We use these software simulators
as filters to weed ouot the gross problems before we go the the
oversubscribed hardware testbed.

Oliver : . . . . Wed, May 15, 7:03PM PDT (-0700 GMT). . . [674 ]
Richard Gerber : repeating myself (sorry) : could you tell if the radiation
levels on the galilean satellites prevent manned exploration ? Thanks

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:03PM PDT (-0700 GMT). . . [675 ]
DOUG@DARKSTAR: I will ask around the folks who work with students around
here.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:03PM PDT (-0700
GMT). . . [676 ]
Bruce P: We will begin getting pictures back from the orbiter some time this
summer. I don't know for sure, but I suspect they will be available over the
internet.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:04PM PDT (-0700 GMT). . . [677 ]
DOUG@DARKSTAR: I will ask around the folks who work with students around
here.

Kevin Zahnle, NASA : . . . . Wed, May 15, 7:04PM PDT (-0700 GMT). . . [678 ]
Could someone please clarify the differences between what the heat of
Jupiter was estimated to be and what it was measured to be? Does the heat
level of Jupiter restrict the types of chemical reactions that occur in the
atmosphere? BB, by "heat" do you mena "temperature?" I don't think
temperatures were surprising. But the lack of water was astonishing.

Philippe PoirŽ, Ph.D. Stusent, eng. : . . . . Wed, May 15, 7:04PM PDT (-0700
GMT). . . [679 ]
What kind of microwave amplification device is used to boost the power of
the signal send to earth ? Twravelling wave tubes, solid state , etc ?

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 7:05PM PDT
(-0700 GMT). . . [680 ]
I would like to hear more about the super-accelerated particles that were
detected leaving the Jovian orbit and any theories concerning their origin.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:06PM PDT (-0700 GMT). . . [681 ]
Well, folks, it's been fun but I'm on my way. Maybe chat with you some other
time.

Billy Biggs, student : . . . . Wed, May 15, 7:06PM PDT (-0700 GMT). . . [682
]
Kevin: I meant temperature, but if it was not different then expected.....
Could you comment on what sort of theories the lack of water disproves?

Bruce P, Amature Astronomer : . . . . Wed, May 15, 7:07PM PDT (-0700 GMT). .
. [683 ]
Richard Gerber: Will the resolution be similar or better than voyager? How
badly has the damaged antenna hindered the return of high resolution images?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:07PM PDT (-0700
GMT). . . [684 ]
Philippe, unless there is an orbiter engineer online at JPL, I'm afraid you
won't get an answer to that question. Here at Ames we have scientists and
engineers from the atmospheric probe with limited knowledge of the orbiter's
subsystem designs. Sorry.

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:07PM PDT (-0700 GMT). . . [685 ]
Trevor - these, I think, were tiny dust grains, probably accelerated by
irregularities in the jovian magnetic field. They showed a periodicity much
like Jupiter's rotation period.

Broadclyst,UK : . . . . Wed, May 15, 7:07PM PDT (-0700 GMT). . . [686 ]
(To Jeff - "I will ask around the...) Thanks that would be BRILLIANT, I
would love the kids to have an 'important' challenge from NASA - not just
some old crusty like me from the local water board. 8-)

Noring, Student at Linkšping Institute of Technology, Sweden : . . . . Wed,
May 15, 7:07PM PDT (-0700 GMT). . . [687 ]
Goodnight everyone! It has been very interesting. Bye!

Jamie Cox : . . . . Wed, May 15, 7:08PM PDT (-0700 GMT). . . [688 ]
NASA and the Galileo team are doing great things lately. I'm looking forward
to the upcoming encounters. It seems even the jaded press is impressed
enough by recent Hubble pictures to put them on the front page. I'm sure
Galileo will wow them again!

Jeff Cuzzi, NASA : . . . . Wed, May 15, 7:08PM PDT (-0700 GMT). . . [689 ]
DOUG@... sure; can't promise but will try.

KK : . . . . Wed, May 15, 7:08PM PDT (-0700 GMT). . . [690 ]
Rich Gerber- Thanks. I shall continue to bug my congressmen's office with
Positive Financial Suggestions for NASA's Well-Being. :^)

Magalhaes Planetary Scientist : . . . . Wed, May 15, 7:09PM PDT (-0700 GMT).
. . [691 ]
Answer to Billy Biggs Question: Do the winds occur in layers? Also, does the
radiation belt or the magnetic field have any effect on the winds? Answer:
The Galileo Probe found that the winds remained strong until the end of the
mission so we only have a lower limit to the the depth of the winds (about
165 km below cloud tops where the Probe mission ended). Your second Q: No
the radiation belts do not affect the winds since the total amount of energy
they can deposit in the atmosphere is quite small and the radiation does not
penetrate very far into the atmosphere. However, an interesting possibility
has recently emerged that may tie the magentic field and the winds on
Jupiter. Recent experiments which placed hydrogen under very high pressures
suggests it becomes conductive at a much shallower depth in Jupiter that we
thought. The possiblity thus exists that the electric currents in Jupiter's
metallic layer, which produce the magnetic field, could also drive the
atmospheric winds observed by the Galileo Probe. This is still speculative.

Kevin Zahnle, NASA : . . . . Wed, May 15, 7:09PM PDT (-0700 GMT). . . [692 ]
BB, lack of water disproves nothing; no one seriously believes that the
oxygen (=water) isn't truly there, somewhere... But now we need to ask - how
does it hide itself? and why?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:09PM PDT (-0700
GMT). . . [693 ]
Oliver: OK, I must have missed the question the first time, but it's a good
one! I can't answer it myself, but I will forward your question to someone
who can (I have your email address.) I believe Galileo measured high-energy
particles in the inner magnetosphere of Jupiter, so it may not have shed any
light on that question. But I'll get back to you via email.

Oliver : . . . . Wed, May 15, 7:11PM PDT (-0700 GMT). . . [694 ]
Richard : Thanks.

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 7:12PM PDT
(-0700 GMT). . . [695 ]
I would like to hear more about the super-accelerated particles that were
detected leaving the Jovian orbit and any theories concerning their origin.

: . . . . Wed, May 15, 7:13PM PDT (-0700 GMT). . . [696 ]
Just wanted to say hello this evening from Cerro Tololo. Looks like you have
a good session going. Bob Hillenbrand, SOFIA

Philippe PoirŽ : . . . . Wed, May 15, 7:13PM PDT (-0700 GMT). . . [697 ]
Thank you everybody, it was really instructive, even if my question didn't
get his answer. Good night from Montreal.

Billy Biggs, student : . . . . Wed, May 15, 7:13PM PDT (-0700 GMT). . . [698
]
Magalhaes: Interesting. Thank you. Do you know how the different cloud types
mix with each other, or if they do? Are different clouds at different
layers?

Greg, Carl Sagan Worshipper : . . . . Wed, May 15, 7:13PM PDT (-0700 GMT). .
. [699 ]
I've read that the probe found that the atmosphere of Jupiter was "drier"
than expected.. How does this affect current theories on Jupiter's origin
(if it does). I mean, is this discovery a "big deal", and if so, why?
Thanks..

Billy Biggs, student : . . . . Wed, May 15, 7:14PM PDT (-0700 GMT). . . [700
]
Kevin: Does this mean that water must exist at much lower altitudes?

KW Spacedteacher : . . . . Wed, May 15, 7:15PM PDT (-0700 GMT). . . [701 ]
Jeff, It's been a long day. Would it be possible to establish life as we
know it on earth on any of the satellites. Is it possible the conditions for
earth lifeforms may exist in the proper equilibrium on the satellites in the
distant future, e.g. Titan.

Broadclyst,UK : . . . . Wed, May 15, 7:16PM PDT (-0700 GMT). . . [702 ]
Ladies, Gentlemen, thank you so much for your time. VERY many congratulation
to the Galileo team of engineers and scientists, not only for the amazing
technical achievement but also for having the time and interest to bring
your 'rocket science' to our students (and me!). The Galileo coverage,
including tonight, has been excellent and MUCH appreciated. Good night. Can
I go back to bed now? - some of us have to go to work in 4 hours time.
Thanks again, Doug@darkstar.zynet.co.uk for Broadclyst Primary and Clyst
Vale Community College, Exeter, UK

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:16PM PDT (-0700
GMT). . . [703 ]
Bruce: The resolution will be considerable better, both in terms of pixels
and closeness. There will be fewer images returned because of the antenna
problem, but there are still expected to be on the order of 4,000 returned
over the next two years.

Kevin Zahnle : . . . . Wed, May 15, 7:17PM PDT (-0700 GMT). . . [704 ]
greg CSW: yes, no water. Lots of ammonia. A place only a space alien could
love. But lack of water is too astonishing to be credible. The water may
well be someplace we didn't look. If it should finally prove that the water
were truly not there, the illuminati would be blundering in the dark...

Moderator2 : . . . . Wed, May 15, 7:17PM PDT (-0700 GMT). . . [705 ]
Hey Bob (Al Here) Leave me alone! I updated the @#$%! Night of the Comet
pages at: button I hope Chile isn't too chilly!

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 7:18PM PDT
(-0700 GMT). . . [706 ]
I would like to hear more about the super-accelerated particles that were
detected leaving the Jovian orbit and any theories concerning their origin.

Bruce P, Amature Astronomer : . . . . Wed, May 15, 7:18PM PDT (-0700 GMT). .
. [707 ]
Richard: Thanks for your answer, I'm looking forward to the pictures as I'm
sure you are.

Kevin Zahnle : . . . . Wed, May 15, 7:19PM PDT (-0700 GMT). . . [708 ]
BB, water might be deep in the hydrogen ocean. Or it might be gathered
towards the poles - both possibilities have some observational support.

Magalhaes Planetary Scientist : . . . . Wed, May 15, 7:20PM PDT (-0700 GMT).
. . [709 ]
To Trevor, Armchair scientist, Dublin, GA: YOUR QUESTION: I read that the
dynamics which cause the high windspeeds on Jupiter were found to be
affected by thermal convection more than expected. Any new news on this?
ANSWER: You might want to take a look at my previous answer to a question by
Broadclyst. The strong winds on Jupiter continued until the end of the Probe
mission at about 165 km below the visible clouds. At these levels, very
little sunlight is being deposited in the atmosphere (and thus many
scientists think it may not produce the winds on Jupiter unlike on Earth
where varying amount of sunlight from equator-to-pole drives the atmospheric
circulation). At depth, the internal heat of Jupiter -- heat left over from
the formation of Jupiter 4.5 billion years ago!-- produces convection in the
deep interior. Several scientists thus think this convection in Jupiter 's
deep interior and the heat it brings up may produce the deep winds. But
there are some of us who do not believe that interpretation is necessarily
correct.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:20PM PDT (-0700
GMT). . . [710 ]
Greg: The lack of water (if it is indeed global on Jupiter) is important
because it has implications for how Jupiter (and other planets) formed and
evolved in the early solar system. It is currently believed that many of the
lighter molecules (such as water) were delivered to the planets by impacts
with comets. Taken at face value, the Galileo results raise questions about
this scenario.

Oliver : . . . . Wed, May 15, 7:20PM PDT (-0700 GMT). . . [711 ]
To all scientists and engineers at Ames and JPL : Many thanks for this
opportunity. Good luck for Orbiter people, we're all waiting this Ganymede
encounter ! To the Probe folks : yours went out in a blaze of glory !
Goodnight to all.

TJ, teacher : . . . . Wed, May 15, 7:20PM PDT (-0700 GMT). . . [712 ]
Anyone - Does the probe data indicate that Jupiter's atmosphere is less
homogeneous than expected? If we "knew then what we know now", would some
kind of multi-probe have been better (if fiscally feasible, of course)?

Billy Biggs, student : . . . . Wed, May 15, 7:21PM PDT (-0700 GMT). . . [713
]
kevin: Care to give me a brief description of the hydrogen ocean? :)

Trevor, Armchair scientist, Dublin, GA : . . . . Wed, May 15, 7:22PM PDT
(-0700 GMT). . . [714 ]
I want to give a big THANK YOU to all who made this informative chat
possible. I hope that this type of interaction will continue. Thanks again
for taking time to talk with your fans. Good luck in the future. We're all
behind you!

Pete : . . . . Wed, May 15, 7:23PM PDT (-0700 GMT). . . [715 ]
Hello Kevin Zahnle: When you say "hydrogen ocean" do you literally mean
liquid hydrogen . . .and if so is there some kind of solid matter
underneath? Is there any solid matter deep below Jupiter's atmosphere?

Pete : . . . . Wed, May 15, 7:24PM PDT (-0700 GMT). . . [716 ]
Hello Kevin Zahnle: When you say "hydrogen ocean" do you literally mean
liquid hydrogen . . .and if so is there some kind of solid matter
underneath? Is there any solid matter deep below Jupiter's atmosphere?

Pete : . . . . Wed, May 15, 7:25PM PDT (-0700 GMT). . . [717 ]
Hello Kevin Zahnle: When you say "hydrogen ocean" do you literally mean
liquid hydrogen . . .and if so is there some kind of solid matter
underneath? Is there any solid matter deep below Jupiter's atmosphere?

Jess, Engineering Student : . . . . Wed, May 15, 7:26PM PDT (-0700 GMT). . .
[718 ]
I'm fascinated - though not well enough informed to ask any intelligent
questions. Keep talking!! Can someone tell me how common these "talk with
the real scientists" chat forums are? What a great thing! Does Nasa, in
particular, do this a lot?

Bruce P, Amature Astronomer : . . . . Wed, May 15, 7:27PM PDT (-0700 GMT). .
. [719 ]
Thanks to all the Galileo people for a chance to visit. I wish you well with
the rest of the mission and I'll follow it on the web and cheer at each
success. Good night all.

Kevin Zahnle : . . . . Wed, May 15, 7:27PM PDT (-0700 GMT). . . [720 ]
bb, ok, as you go deep into Jupiter the hydrogen gets denser and denser and
denser and denser. Eventually the stuff turns to metal, around 1.5 million
atmospheres pressure.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:28PM PDT (-0700
GMT). . . [721 ]
Jess, It's hard to keep talking when the questions slow down.

Marc : . . . . Wed, May 15, 7:28PM PDT (-0700 GMT). . . [722 ]
Charlie, You wrote about Casini/Huygens probes. Are those two missions or
one? I've heard about Cassini, but not Huygens. What is that about

Kevin Zahnle : . . . . Wed, May 15, 7:29PM PDT (-0700 GMT). . . [723 ]
Pete, the hydrogen is supercritical. Call it liquid, call it gas; its not
really either. Best to call it fluid. But its dense!

Jess, Engineering Student : . . . . Wed, May 15, 7:29PM PDT (-0700 GMT). . .
[724 ]
CS - good point. Wish I could help...I'd hate to just come on and say "So,
someone brief me on the whole mission." (though knock yourself out if you're
up to it! Honestly, I'm interested but hoped to let others ask the
questions)

Bruce P, Amature Astronomer : . . . . Wed, May 15, 7:30PM PDT (-0700 GMT). .
. [725 ]
Thanks to all the Galileo people for a chance to visit. I wish you well with
the rest of the mission and I'll follow it on the web and cheer at each
success. Good night all.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:30PM PDT (-0700
GMT). . . [726 ]
Marc, like Galileo, the sacecraft to Saturn consists of two parts. The
orbiting spacecraft is named Cassini. The entry probe is named Huygens, and
will enter into the atmosphere of Saturn's moon, Titan, instead of into the
planet itself.

Billy Biggs, student : . . . . Wed, May 15, 7:30PM PDT (-0700 GMT). . . [727
]
Kevin: There was some talk about liquids in Jupiters atmosphere in some of
the press releases. Is this what they were refering to?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:31PM PDT (-0700
GMT). . . [728 ]
Trevor: The Science special issue on Galileo discusses the energetic
particle fluxes on pgs. 856-857. The major puzzle, according to the article,
are the particle fluxes at 1.5 Jupiter radii. Possible sources are from
cosmic ray interactions with either ring material or the Jovian atmosphere.

Billy Biggs, student : . . . . Wed, May 15, 7:31PM PDT (-0700 GMT). . . [729
]
Also, I heard that the ammonia clouds were ice, is this
true/possible/way-out-there?

TassiloLasa : . . . . Wed, May 15, 7:31PM PDT (-0700 GMT). . . [730 ]
Hi. I'm curious re Io. What is the Io "torus"?

Marc : . . . . Wed, May 15, 7:32PM PDT (-0700 GMT). . . [731 ]
Charlie: What lessons did you learn that don't apply to Huygens? And why
don't they apply? What is different?

Moderator2 : . . . . Wed, May 15, 7:34PM PDT (-0700 GMT). . . [732 ]
To Jeff - We haven't done Webchats a lot. But recent success with NIght of
the Comet, and this one are a good case for having more. This group (K-12)
Internet Intiative is planning to some on Women of NASA and Mars in the Near
Future. Keep checking in button in the What's New and Online Activities
section.

Pete : . . . . Wed, May 15, 7:34PM PDT (-0700 GMT). . . [733 ]
Charlie: will you be involved with the Saturn mission as well?

Kevin Zahnle : . . . . Wed, May 15, 7:34PM PDT (-0700 GMT). . . [734 ]
BB, ammonia clouds are ice crystals on top, possibly droplets below.

pete (mech eng grad student) : . . . . Wed, May 15, 7:35PM PDT (-0700 GMT).
. . [735 ]
Charlie, on Cassini: does it do a gravity assist of Jupiter? or just venus
and earth? Can we expect useful Jupiter observations from it as well as the
Saturn/Titan stuff?

Pete : . . . . Wed, May 15, 7:35PM PDT (-0700 GMT). . . [736 ]
Charlie: will you be involved with the Saturn mission as well?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:35PM PDT (-0700
GMT). . . [737 ]
TassiloLasa: There is a torus of charged particles surrounding the orbit of
the moon Io.

: . . . . Wed, May 15, 7:36PM PDT (-0700 GMT). . . [738 ]
Jake, Amateur Engineer. To Charles Sobbeck. Hello. Have you been able to
find the answers to my two questions from earlier on? Galileo's flyby
velocity of Ganymede compared to the joviasn escape velocity in the moon's
vicinity; and how many images, compressed or otherwise, can the
tape-recorder now hold?

Pete : . . . . Wed, May 15, 7:36PM PDT (-0700 GMT). . . [739 ]
Charlie: will you be involved with the Saturn mission as well?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:36PM PDT (-0700
GMT). . . [740 ]
Marc, the Huygens mission has considerable differences compared to Galileo.
First off, entering a moon with only 0.16 earth gravity, makes it much
easier than the entry into Jupiter, being pulled in by its tremendous
gravitational field. Also, whereas Jupiter's atmosphere starts off cold up
high and then becomes very hot lower down, on Titan it just stays cold. And
on Titan, the pressure reaches only 2 bars at the surface, whereas Jupiter's
pressure just keeps building.

Marc : . . . . Wed, May 15, 7:38PM PDT (-0700 GMT). . . [741 ]
To KK. I write from Washington DC. One thing I know is that the politicos on
the Hill are more influenced by snailmail then by Email. So sending Email in
support of NASA's science missions is good. Sending real letters is better.
I think the theory goes that if it is harder to do, then you obviously care
more. And real mail is indeed harder then Email once you are connected

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:39PM PDT (-0700
GMT). . . [742 ]
Pete, I am not directly involved in the Cassini/Huygen mission. I'm afraid I
don't know the specifics about the Cassini trajectory. I know it will use
gravity assists, and will take something like 7 years to get there, but
that's about it.

: . . . . Wed, May 15, 7:40PM PDT (-0700 GMT). . . [743 ]
Jake, Amateur Engineer. To Charles Sobeck. Hello. Have you been able to find
the answers to my two questions from earlier on? Galileo's flyby velocity of
Ganymede compared to the jovian escape velocity in the moon's vicinity; and
how many images, compressed or otherwise, can the tape-recorder now hold?

Magalhaes Planetary Scientist : . . . . Wed, May 15, 7:41PM PDT (-0700 GMT).
. . [744 ]
Answer to: TJ, teacher :Anyone - Does the probe data indicate that Jupiter's
atmosphere is less homogeneous than expected? If we "knew then what we know
now", would some kind of multi-probe have been better (if fiscally feasible,
of course)? ANSWER: A multi-probe would definitely have been great! We knew
going in that Jupiter is a very complex and varied world. If money would
have allowed a multi-probe that is clearly what would have been preferable.
However, it was generally believed that at deeper levels the atmosphere
would be more homogeneous with latitude and longitude. Observations of
lightning on Jupiter and radio observations from telecopes on the ground
suggested that this view-- resulting from theoretical arguments -- was
wrong. The Probe seems to have shown that the original ideas about Jupiter's
depths being pretty uniform with latitude and longitude are incorrect.
Anyone - Does the probe data indicate that Jupiter's atmosphere is less
homogeneous than expected? If we "knew then what we know now", would some
kind of multi-probe have been better (if fiscally feasible, of course)?

Marc : . . . . Wed, May 15, 7:41PM PDT (-0700 GMT). . . [745 ]
So if Huygens is only going to encounter 2 bars of pressure, and a much
slower entry speed, will it keep operating until it goes boom on the
surface?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:43PM PDT (-0700
GMT). . . [746 ]
Jake, sorry, my station went down for awhile, I never saw your questions.
Even more unfortunate, now that I've seen them, I don't know the answers! I
know the spacecraft will never be able to attain Jovian escape velocity, but
I don't know how close it will get. The quantity of images that will fit on
the tape recorder depends on the siae and resolution of the images.

: . . . . Wed, May 15, 7:43PM PDT (-0700 GMT). . . [747 ]
Jake, Amateur Engineer. To Charles Sobeck. Hello. Have you been able to find
the answers to my two questions from earlier on? Galileo's flyby velocity of
Ganymede compared to the jovian escape velocity in the moon's vicinity; and
how many images, compressed or otherwise, can the tape-recorder now hold?

Pete : . . . . Wed, May 15, 7:44PM PDT (-0700 GMT). . . [748 ]
Richard: how long will it take for data to travel form Galileo to earth and
how often will it transmit?

TassiloLasa : . . . . Wed, May 15, 7:44PM PDT (-0700 GMT). . . [749 ]
Thank you Richard. And a "picture" of these charged particles would look
like a "donut?"

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:45PM PDT (-0700
GMT). . . [750 ]
Marc, the expectation is that Huygens will survive the surface landing, at
least for a while. In fact, the probe's design accounts for the possibility
that the surface may consist of a "Methane Ocean", and it would float.

Thrak, lint magnate : . . . . Wed, May 15, 7:46PM PDT (-0700 GMT). . . [751
]
Hollingsworth, you there ??

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:47PM PDT (-0700
GMT). . . [752 ]
TassiloLasa: That's right, the sodium and sulfur in the torus come from Io.

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 7:47PM PDT (-0700
GMT). . . [753 ]
Speak, Hobbes!

Marc : . . . . Wed, May 15, 7:48PM PDT (-0700 GMT). . . [754 ]
Charlie, How wierd about a floating Probe. I was surprised earlier when you
stated that you knew the Probe would work. I understood that the temperature
just off the nose of the Probe was hotter then the surface of the Sun. How
do you test for things like that? and how hot was the temp at the nose
itself?

hobbes : . . . . Wed, May 15, 7:48PM PDT (-0700 GMT). . . [755 ]
I believe I did send a message, guess I am not too familiar with this type
of chat system

: . . . . Wed, May 15, 7:49PM PDT (-0700 GMT). . . [756 ]
Jake, Amateur Engineer. Ooops! I had a little software problem. I heard that
the orbiter's tape-recorder could hold upto 4,000 black & white compressed
images. I wanted to know if that were true. Sorry about the previously
redundant questions.

hobbes : . . . . Wed, May 15, 7:51PM PDT (-0700 GMT). . . [757 ]
I was wondering if there were any plans that we would be sending another
probe to revisit jupiter with the knowledge now to be better prepared for
what is out there?

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 7:51PM PDT (-0700
GMT). . . [758 ]
hobbes, This is my first time, as well. But I am here to serve the public!

Billy Biggs, student : . . . . Wed, May 15, 7:51PM PDT (-0700 GMT). . . [758
]
Kevin: If I have a few questions after this chat, would you mind it if I
emailed you?

Pete : . . . . Wed, May 15, 7:51PM PDT (-0700 GMT). . . [759 ]
Charlie . . .How long does it take for data to travel from Galileo to Earth
and how often will it transmit?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:52PM PDT (-0700
GMT). . . [760 ]
Pete: It takes about 45 minutes (depending on where Jupiter and the Earth
are) for signals to reach Earth from Jupiter. The orbiter will be
transmitting as much as possible. With new software, it is expected that
data will be able to be sent at a maximum of 160 bits per second.

Steve Collins Galiloe Orbiter Engineering team : . . . . Wed, May 15, 7:52PM
PDT (-0700 GMT). . . [761 ]
Steve Collins here (Orbiter engineering team attitude control) . I'm back
online from home (fwhew!)

TassiloLasa : . . . . Wed, May 15, 7:52PM PDT (-0700 GMT). . . [762 ]
Thanks again, Richard. And if Jupiter is in the center of the "donut hole,"
what is the diameter of the donut as compared to the diameter of Jupiter?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:53PM PDT (-0700
GMT). . . [763 ]
Marc, the peak temperatures occured in the shock layer, just infront of the
Probe's nose. The actual temperature of the probe was limited to the
vaporization temperature of the carbon heatshield (a number I don't have
with me right now). The heatshield material, was tested here at Ames in an
"arcjet" facility (a hypersonic, ionized gas wind tunnel, as well as with
high powered lasers.

Steve Collins Galiloe Orbiter Engineering team : . . . . Wed, May 15, 7:53PM
PDT (-0700 GMT). . . [764 ]
Jamie Cox: I saw a message you posted earlier about software simulation of
Galileo. I've been working on the Orbiter software sim for the last several
months. If you have specific questions.

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 7:53PM PDT (-0700
GMT). . . [765 ]
hobbes, budget rules, and there are arbitrary political divisions. As best I
can tell, as long as Cassini mission to Saturn consumes big bucks, there
will be no missions deeper than Mars. Unless a Pluto mission gets $$; Pluto
is the exception

Pete : . . . . Wed, May 15, 7:54PM PDT (-0700 GMT). . . [766 ]
Charlie . . .sorry about the redundant question . . . I wasn't sure if
Richard received my question . . .thanks Richard!

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:54PM PDT (-0700
GMT). . . [767 ]
Jake: I think what you might have seen was my response to a question about
images. I stated that the orbiter was expected to send back 4,000 images,
but that was over a two-year period.

Magalhaes Planetary Scientist : . . . . Wed, May 15, 7:54PM PDT (-0700 GMT).
. . [768 ]
General call to folks out there: How many people are familiar with the
Galileo Probe Homepage? How did you learn about this event?

hobbes : . . . . Wed, May 15, 7:55PM PDT (-0700 GMT). . . [769 ]
I learned about this event on the astronomer's mailing list.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 7:55PM PDT (-0700
GMT). . . [770 ]
Jake, the number of 4,000 images refers to the total number of images we
expect to get from the spacecraft over its nominal life of two years. They
will not all reside on the tape recorder at the same time.

Marc : . . . . Wed, May 15, 7:55PM PDT (-0700 GMT). . . [771 ]
Hi Steve, Welcome back. I still remember the excitement I felt as you typed
from the backroom during the Jupiter Insertion burn, as you kept us up to
date on what was really going on. You can't imagine how exciting it is for
regular folks (but space fans) to feel connected to real space missions in
real time. So I understood that the Orbiter was getting a whole new bunch of
software. Did that happen yet?

Pete : . . . . Wed, May 15, 7:56PM PDT (-0700 GMT). . . [772 ]
Charlie . . .sorry about the redundant question . . . I wasn't sure if
Richard received my question . . .thanks Richard!

Sally Forth : . . . . Wed, May 15, 7:56PM PDT (-0700 GMT). . . [773 ]
How are you proceeding to analyze the Probe Data? Are you looking to see if
you found what you expected?

Jessica, Engineering Student : . . . . Wed, May 15, 7:56PM PDT (-0700 GMT).
. . [774 ]
I learned about this event on the "Today @ Nasa" page.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 7:58PM PDT (-0700
GMT). . . [775 ]
Tassilo: Io cuts across Jupiter's magnetic field lines, generating an
electric current. Though small compared to the tidal heating, this current
may carry more than 1 trillion watts. It also strips some material away from
Io which forms a torus of intense radiation around Jupiter

Marc : . . . . Wed, May 15, 7:58PM PDT (-0700 GMT). . . [776 ]
Charlie: another fact that I can't quite get my head around is within a few
minutes, the Probe decellerated from 100,000 MPH to 300 MPH. Can you
describe the engineering issues involved in surviving just that kind of
rapid deceleration. Or is that not really such a big issue?

Billy Biggs, student : . . . . Wed, May 15, 7:58PM PDT (-0700 GMT). . . [777
]
Magalhaes: I learned of this from the JUP update and from the homepage,
which I have been searching often for updated Galileo information.

hobbes : . . . . Wed, May 15, 7:59PM PDT (-0700 GMT). . . [778 ]
could this magnetic field be used in powering future probes as the teathered
sattelite attempted?

Steve Collins Galiloe Orbiter Engineering team : . . . . Wed, May 15, 8:00PM
PDT (-0700 GMT). . . [779 ]
Marc: The "in flight load" as we call it is going on even as we speak (er
type...) We've loaded the new attitude control computer software that
contains the data compression code and are in the process of loading the CDS
computer software that implements "packetized" telemetery and the new coding
schemes.

Pete : . . . . Wed, May 15, 8:00PM PDT (-0700 GMT). . . [780 ]
Richard: Is it theoretically possible for a spacecraft or probe to safely
harness some of this electrical current as a long term energy source?

pete (mech eng grad student) : . . . . Wed, May 15, 8:01PM PDT (-0700 GMT).
. . [781 ]
I asked before, but perhaps you new guys have an opinion: Can you see a fast
cheap Discovery class mission to Jupiter or beyond being organised in the
near future?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:01PM PDT (-0700
GMT). . . [782 ]
Sally, The probe data has now all been returned from the orbiter. We had to
replay certain portions that we lost due to things like antenna problems
here on the ground, and it has taken some time to patch it all together into
one long uniterrupted error free string. We then separate the data out for
each of the instruments we flew, and send each investigator only data from
his own instrument. The investigator and his team then analize the data to
determine what they can learn about Jupiter, and how that compares to our
predictions. The first published results appear in this weeks edition of the
journal SCIENCE.

Jennifer, Off-site Monitor : . . . . Wed, May 15, 8:01PM PDT (-0700 GMT). .
. [783 ]
I'll be signing off in a few minutes. Thanks all for your excellent
participation! The chat continues for about another hour.

Marc : . . . . Wed, May 15, 8:02PM PDT (-0700 GMT). . . [784 ]
Steve, So is the Spacecraft pretty much dedicated to getting the new
software..ie is nothing else really going on ? When will the software upload
be done?

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:02PM
PDT (-0700 GMT). . . [785 ]
Marc: Glad you were able to tune into the JOI stuff. It was really a blast
to be able to share it with the net real time. It also gave me something to
do so my imagination didn't run away with me. My last spacecraft disappeared
just before orbit insertion...

pete (mech eng grad student) : . . . . Wed, May 15, 8:03PM PDT (-0700 GMT).
. . [786 ]
Magalhaes: And *I* heard about it from Ron Baalke on Sci.space.*

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:03PM PDT (-0700
GMT). . . [787 ]
Tassilo: As for the thickness of the torus: it's small, about the size of
the moon itself.

TassiloLasa : . . . . Wed, May 15, 8:04PM PDT (-0700 GMT). . . [788 ]
Richard, I'm trying to visualize the size of Io's torus, ie, the size of the
"donut," as compared to the size of Jupiter. Can the torus be visualized in
this way?

Marc : . . . . Wed, May 15, 8:04PM PDT (-0700 GMT). . . [789 ]
Steve. Oh, the Mars Observer. What a bummer. Had you been working on both
missions simultaneously? Are there any folks at JPL still working to
understand what happened to Mars Observer?

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 8:05PM PDT (-0700
GMT). . . [790 ]
pete, I know nothing about costing missions, but I can't seen any mission to
Jupiter other than a cheap one. Our Fearless Leader believes that where
there is a Will, there is a way. First, lets see if we can drop a probe
cheap into an easy target like Venus, then lets go for Jupiter near the
pole.

Sally F : . . . . Wed, May 15, 8:05PM PDT (-0700 GMT). . . [791 ]
Thanks Charlie, I attended the first press conference and it struck me that
there is a huge gap between the science being discovered and the press's
ability to comprehend enough to ask intelligent questions. I think this
project is helping to close the gap.

Dennis, space fan : . . . . Wed, May 15, 8:06PM PDT (-0700 GMT). . . [792 ]
Kevin: You mentioned that hydrogen was supercritical when referring to the
hydrogen ocean. Are you saying, then, that the hydrogen assumes different
levels of mass, ranging from gas to liquid to an almost metalic-like form at
the bottom as pressure becomes greater?

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:07PM
PDT (-0700 GMT). . . [793 ]
Marc: We need to pretty much take over the whole spacecraft while we do the
in flight load, so I doubt we are doing any science observations during this
time. (Don't know for sure though...) We do have to keep up on some routine
activites that we do all the time like "thruster flushes". I'm not sure of
the exact schedule, but I the the CDS part of the load takes about a week.
Then there will be some follow on work and a period of testing. I spent
several hours yesterday checking memory read outs of the data compression
code byte by byte for example.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:07PM PDT (-0700
GMT). . . [794 ]
Pete: That's a good thought! I'm not sure how it could be engineered, but
perhaps somebody should take a look at that possibility.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:07PM PDT (-0700
GMT). . . [795 ]
Marc, decelerating from 100,000 mph to a couple hundred in just minutes is
an enormous technical challange! In addition to the (relatively) simple
problem of surviving 230 g's, there is a tremendous amount of kinetic energy
that must be dumped. If this energy were simply absorbed, the probe would
have easily burned up. There was considerable effort spent to figure out
just how to do this, and tests were preformed as early as the sixties with
models in ballistic ranges, Earth entry vehicles, and of course, although
the problem is much easier, at Venus, with the Pioneer Venus probes.

KK : . . . . Wed, May 15, 8:07PM PDT (-0700 GMT). . . [796 ]
Marc- To ansewer your question, yes I do. :)

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 8:09PM PDT (-0700
GMT). . . [797 ]
D, SF: supercritical means that the hydrogen is too dense and hot to have
discrete phase transitions. That is, you don't have surfaces. As you go
deeper, the gases just keep getting thicker

Dennis, space fan : . . . . Wed, May 15, 8:10PM PDT (-0700 GMT). . . [798 ]
Kevin: You mentioned that hydrogen was supercritical when referring to the
hydrogen ocean. Are you saying, then, that the hydrogen assumes different
levels of mass, ranging from gas to liquid to an almost metalic-like form at
the bottom as pressure becomes greater?

pete (mech eng grad student) : . . . . Wed, May 15, 8:10PM PDT (-0700 GMT).
. . [799 ]
Kevin, you suggest the Jovian poles next. What makes them so interesting?
Just a change of scenery compared to the equator?

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:10PM
PDT (-0700 GMT). . . [800 ]
Marc: I was full time on MO and transfered to GLL several months after the
failure. There are no ongoing MO failure activites that I know of, but
projects continue to learn from the events. Galileo did a very thorough
review of the propulsion system and other hardware looking for problems the
spacecraft might have in common, for example

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:11PM PDT (-0700
GMT). . . [801 ]
Tasillo: Maybe it could be thought of as a tail of particles trailing the
moon, about the same size of the moon. Sometimes the torus does not even
appear to extend completely around Jupiter.

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 8:12PM PDT (-0700
GMT). . . [802 ]
pete, sure, poles. must find water!

Kevin Zahnle, Big Time Scientist : . . . . Wed, May 15, 8:12PM PDT (-0700
GMT). . . [803 ]
pete, specifically, 49 degrees north, which is where the lightning is.

Jessica, Engineering Student : . . . . Wed, May 15, 8:13PM PDT (-0700 GMT).
. . [804 ]
Must be leaving (as quietly as I came)...This is an excellent idea, even for
an observer like myself. Looking forward to future online chat forums (both
Women of NASA and Mars forums sound great!) Can't wait!

Dennis, space fan : . . . . Wed, May 15, 8:15PM PDT (-0700 GMT). . . [805 ]
K: That is amazing, almost too much to comprehend! It creates a fascinating
Mental image. With the information gathered here, I can almost take myself
there and see it! I want to thank you all again for your time and your
wonderful work. See you again. G'night.

Marc : . . . . Wed, May 15, 8:15PM PDT (-0700 GMT). . . [806 ]
Charlie, 230 G's. Geez. How do you test for something like that. Or is it
just well understood mechanical engineering? Does 230 G's effect things like
the operation of electrical systems? I mean, does the deceleration change
the way the electricity flows, the way the computers compute, etc?

NASA CRITIC : . . . . Wed, May 15, 8:16PM PDT (-0700 GMT). . . [807 ]
Will we see some pictures of IO and Europa the next time galileo passes by
them both, and how many months after the encounter will it take to relay
them to earth at 16 bits/sec?

Marc : . . . . Wed, May 15, 8:17PM PDT (-0700 GMT). . . [808 ]
Is there any plan to take the results of this chat and archive it so we can
look back to what a fun time we had?

TassiloLasa : . . . . Wed, May 15, 8:17PM PDT (-0700 GMT). . . [809 ]
Richard. Ahhhh...thank you. "Visual" explanations are most helpful!

dinob : . . . . Wed, May 15, 8:17PM PDT (-0700 GMT). . . [810 ]
hello

dinob : . . . . Wed, May 15, 8:19PM PDT (-0700 GMT). . . [811 ]
discussion topic?

pete (mech eng grad student) : . . . . Wed, May 15, 8:19PM PDT (-0700 GMT).
. . [812 ]
Kevin, Ahah! And perhaps we'll find penguin-like beasts on the iceberg-like
floes drifting in the hydrogen seas! Thanks Kevin, et al., for all your time
and info.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:19PM
PDT (-0700 GMT). . . [813 ]
dinob: start one!

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:20PM PDT (-0700
GMT). . . [814 ]
Tasillo: I've done some more research and I have to ammend my Io torus
comments! See the image at: button There you can see that the torus is
larger than I stated.

KK : . . . . Wed, May 15, 8:20PM PDT (-0700 GMT). . . [815 ]
Yes. Sleep I must. 1100 here @ KSC. Work tommarrow. Enjoyed Galileo WebChat!
:) MANY thanks to you all! Very informative AND fun :) I learned quite a
bit. Hope this becomes a regular happening and look forward to more! :^]
G'Night :))

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:20PM PDT (-0700
GMT). . . [816 ]
Marc, 230 G's doesn't effect the fundamental behavior of conductors or
semiconductors, but you can imagine the concerns about circuit boards
flexing and traces cracking! Testing is straightforward though (sort of)..
You simply put the hardware on a centrifuge and spin it up. We did this to
all the probe instruments and subsystems. However, once it was assembled,
the full probe was too massive for any centifuge to spin it to the qual
level of 340 G's. The best we could do at that level was to spin it to 200
G's.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:21PM PDT (-0700
GMT). . . [817 ]
Tassilo: Oops! I apologize for misspelling your name.

Thrak, Big Time Scientist : . . . . Wed, May 15, 8:21PM PDT (-0700 GMT). . .
[818 ]
pete, water is the key. Until we find, Jupiter will be laughing at us

Nasa Critic : . . . . Wed, May 15, 8:22PM PDT (-0700 GMT). . . [819 ]
Whgen is the second Europa encounter Late Fall? and will we be taking
pictures on that encounter If so how many months at 16 bits/sec will it
taake for us to see them?

Pete : . . . . Wed, May 15, 8:22PM PDT (-0700 GMT). . . [820 ]
Steve Collins: Sincere condolences on the Mars Observer issue. Congrats on a
fantastic success with Galileo! Richard Gerber mentioned a few minutes ago
about the likely existence of an electrical current generating as much as a
trillion watts. He and I thought that it might be worth it to look into
sending a science vessel to harness this electrical current as a long term
or permanent energy source. Just a thought for future missions.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:22PM
PDT (-0700 GMT). . . [821 ]
pete: penguin-beasts on hydrogen ice floes... ah what a conservative view.
What we'll find will be *much* more interesting than *that*...

Karen, moderator : . . . . Wed, May 15, 8:22PM PDT (-0700 GMT). . . [822 ]
Marc, archives of this WebChat will be available at button

Louis : . . . . Wed, May 15, 8:22PM PDT (-0700 GMT). . . [823 ]
Richard, what's the Io torus ?

Webmaster@quest : . . . . Wed, May 15, 8:24PM PDT (-0700 GMT). . . [824 ]
Shut down in 40 minutes --- We will archive this session to a Webpage -
check back in a few days.

Marc : . . . . Wed, May 15, 8:24PM PDT (-0700 GMT). . . [825 ]
Karen, Cool. Thanks

Billy Biggs, student : . . . . Wed, May 15, 8:25PM PDT (-0700 GMT). . . [826
]
Would anybody affiliated with Galileo be willing to answer a few questions
via email after this chat? I just know I'm going to think up something
interesting later... :)

Marc : . . . . Wed, May 15, 8:26PM PDT (-0700 GMT). . . [827 ]
Charlie. What role did you play in the Probe's design. Did you get to
actually design it, or was it more like that you specified it and then the
lowest bidder meeting the specs got to design it?

dinob : . . . . Wed, May 15, 8:26PM PDT (-0700 GMT). . . [828 ]
Karen. is this open discussion?

Nasa Critic : . . . . Wed, May 15, 8:26PM PDT (-0700 GMT). . . [829 ]
Does one need to stroke the folks at JPL and call them heros to get an
answer?

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:27PM PDT (-0700
GMT). . . [830 ]
Louis: Here's info from the excellent Web pages: The Nine Planets. o also
cuts across Jupiter's magnetic field lines, generating an electric current.
Though small compared to the tidal heating, this current may carry more than
1 trillion watts. It also strips some material away from Io which forms a
torus of intense radiation around Jupiter (picture 23). Particles escaping
from this torus are partially responsible for Jupiter's unusually large
magnetosphere. This excellent resource is available at: button

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:27PM
PDT (-0700 GMT). . . [831 ]
Sure, Billy I'd be up for that... Steven.M.Collins@jpl.nasa.gov Can't
promise I'll be able to answer them all though...

dinob : . . . . Wed, May 15, 8:27PM PDT (-0700 GMT). . . [832 ]
Karen. is this open discussion?

Thrak, Big Time Scientist : . . . . Wed, May 15, 8:28PM PDT (-0700 GMT). . .
[833 ]
Critic, dunno. we typists are calculating...

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:28PM PDT (-0700
GMT). . . [834 ]
Louis: Here's info from the excellent Web pages: The Nine Planets. o also
cuts across Jupiter's magnetic field lines, generating an electric current.
Though small compared to the tidal heating, this current may carry more than
1 trillion watts. It also strips some material away from Io which forms a
torus of intense radiation around Jupiter (picture 23). Particles escaping
from this torus are partially responsible for Jupiter's unusually large
magnetosphere. This excellent resource is available at: button

Marc : . . . . Wed, May 15, 8:28PM PDT (-0700 GMT). . . [835 ]
NASA critic: back off. these guys are probably answering as many questions
as they can...have you noticed there is more questions then time to answer.
Why not just ask again instead of copping an attitude?

Billy Biggs, student : . . . . Wed, May 15, 8:29PM PDT (-0700 GMT). . . [836
]
Steve: Thanks!

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:30PM PDT (-0700
GMT). . . [837 ]
Marc, I had little role in designing the Probe, or even generating the
specifications. When I hired on 17 years ago, the design was already well
along. My real involvement started with system integration and test, and
doing the verifacation the the Probe's performance met its requirements.

dinob : . . . . Wed, May 15, 8:31PM PDT (-0700 GMT). . . [838 ]
Please explain how to " button :

Nasa Critic : . . . . Wed, May 15, 8:31PM PDT (-0700 GMT). . . [839 ]
Im not upset about the slow response to answereing a question its about the
mistakes Nasa seems to make over and over again.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:33PM
PDT (-0700 GMT). . . [840 ]
Critman: the way I understand the data return strategy, right after the
encounter we start sending the data back as fast as we can. Some priority is
given to SSI pictures of "public interest" so that within a week or two of
encounter we should have something to show for our work. The remainder of
the pictures and other science data are returned over the course of the
entire orbit. I'm at home, so I don't have the flyby schedule to give you
exact encounter dates. I'll bet those are on the GLL web site somewhere.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:33PM PDT (-0700
GMT). . . [841 ]
dinob: When we type in a URL it seems to get converted, by the chat
software, into the "button" that you see. At least on the machine I'm using,
clicking on the word "button" takes you to the specified page.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:34PM
PDT (-0700 GMT). . . [842 ]
Critic: Feel free to join us and help us do it right...

Nasa Critic : . . . . Wed, May 15, 8:35PM PDT (-0700 GMT). . . [843 ]
A first step would be to admit that the shuttle was a bad idea.

Marc : . . . . Wed, May 15, 8:35PM PDT (-0700 GMT). . . [844 ]
Oh well. My wife's home and it's here birthday today so it is time to
celebrate something other then space. Thanks so much for this great
opportunity to get my space jollies fulfilled. Good night!

My Dad Won't Let me Use My Real Name (Student) : . . . . Wed, May 15, 8:36PM
PDT (-0700 GMT). . . [845 ]
Hi!

Thrak, Big Time Scientist : . . . . Wed, May 15, 8:36PM PDT (-0700 GMT). . .
[846 ]
NCAA Critic: Student athletes?! A sham! Look at Nebraska, for instance.
Lawrence Phillips, a good kid who just idolized O.J. a little too much? And
so they cancel the scholarship of the girl he beat up? oh, sorry, I thought
that was NCAA Critic...

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:36PM
PDT (-0700 GMT). . . [847 ]
Critic: So you advocate dumping the shuttle? In favor of?...

My Dad Won't Let me Use My Real Name (Student) : . . . . Wed, May 15, 8:36PM
PDT (-0700 GMT). . . [848 ]
I think that NASA has some good ideas but needs to expand on them

Magalhaes Planetary Scientist : . . . . Wed, May 15, 8:37PM PDT (-0700 GMT).
. . [849 ]
TO: Nasa Critic : YOUR QUESTION: Whgen is the second Europa encounter Late
Fall? and will we be taking pictures on that encounter If so how many months
at 16 bits/sec will it taake for us to see them? ANSWER: The first Europa
encounter occurs near the end of this year, as I recall. The images are
about 800 pixels by 800 pixels in size and use eight bits to represent each
pixels brightness. Using our handy dandy calculator, this implies one full
image would take about 3.7 days to arrive on Earth. With the new compression
algorithms on the spacecraft, the effective transmission rate will be about
160 bits/ sec so one image would take about 0.3 days to arrive on the
ground.

My Dad Won't Let me Use My Real Name (Student) : . . . . Wed, May 15, 8:37PM
PDT (-0700 GMT). . . [850 ]
THE NATIONAL AEROSPACE PLANE! (Which I believe they have already made and
are flying as we speak)

My Dad Won't Let me Use My Real Name (Student) : . . . . Wed, May 15, 8:38PM
PDT (-0700 GMT). . . [851 ]
But again---] I'm biased. :-)

Nasa Critic : . . . . Wed, May 15, 8:38PM PDT (-0700 GMT). . . [852 ]
The shuttle was billed as a cheaper way to get payloads into orbit. Would
you agree it hasnt lived up to expectations fiscally?

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:39PM PDT (-0700
GMT). . . [853 ]
Please, big words are hard to take in at my age...keep it cool, huh?

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:39PM
PDT (-0700 GMT). . . [854 ]
Critic: I can't argue with you there...

Nasa Critic : . . . . Wed, May 15, 8:39PM PDT (-0700 GMT). . . [855 ]
Magalhaesthe first encounter allready occured. Nasa didnt get any data.

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:39PM PDT (-0700
GMT). . . [856 ]
I love the spce program! We will beat the other countries to any planet,
etc...

Dr. Thrak : . . . . Wed, May 15, 8:40PM PDT (-0700 GMT). . . [857 ]
Dear MDWLmUMRN: Big Dumb Boosters. And yes, Goldin *does* understand that.
But its not his decision...

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:40PM PDT (-0700
GMT). . . [858 ]
so...who here is responsible for the tech stuff on Galileo?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:41PM PDT (-0700
GMT). . . [859 ]
Dad, The National Aerospace Plane, never got off the ground (so to speak) it
died before it was ever fully born when it ran into serious technical
difficulties, looked to require an awful lot of money and couldn't clearly
define what use it would be put to.

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:41PM PDT (-0700
GMT). . . [860 ]
?

hobbes (astronomer) : . . . . Wed, May 15, 8:41PM PDT (-0700 GMT). . . [861
]
I felt the repair missions which the shuttle performed with the hubble,
instead of trashing it and sending up another one.

Louis : . . . . Wed, May 15, 8:41PM PDT (-0700 GMT). . . [862 ]
I wanted to tell all you NASA people who are on here how much I learned from
reading all the "On Line from Jupiter" emails you sent out this winter. Made
me realize for the first time since Apollo how much is involved in executing
these operations. Do you know how many people were working on Galileo?

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:42PM PDT (-0700
GMT). . . [863 ]
Thanks for the info Charlie! Appreciate it!

Magalhaes Planetary Scientist : . . . . Wed, May 15, 8:42PM PDT (-0700 GMT).
. . [864 ]
TO: Nasa Critic : YOUR QUESTION: The shuttle was billed as a cheaper way to
get payloads into orbit. Would you agree it hasnt lived up to expectations
fiscally? ANSWER: You will not find anyone of us contesting that statement.
From the start the community of space scientists inside and outside NASA
have recognized it is and was and will continue to be an overly expensive
experimental vehicle-- not ready for regular routine lifting.

Anonymous (No name guy from before) : . . . . Wed, May 15, 8:42PM PDT (-0700
GMT). . . [865 ]
Bye! *poof*

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:42PM PDT (-0700
GMT). . . [866 ]
Louis: I read earlier that 10,000 people were involved in some way with
Galileo.

Nasa : . . . . Wed, May 15, 8:45PM PDT (-0700 GMT). . . [867 ]
There were people telling you guys it was a mistake 2 decades ago. People
like James Van Allen, but now since you have it you must use it. Thats why
Gaalileo was designed to go on the shuttle. To give the shuttle something to
do.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:45PM
PDT (-0700 GMT). . . [868 ]
Louis: thanks. That was the whole idea. Flying spacecraft is increadibly
difficult and increadibly fun at the same time. Most of us feel super lucky
to be able to contribute and sharing the excitement of it with "the
customer" is one of the best parts.

hobbes, astronomer : . . . . Wed, May 15, 8:45PM PDT (-0700 GMT). . . [869 ]
The shuttle does alot more than just send up payloads. I feel it does alot
of different tasks, with the experiements done in space. repair work and
upgrading of differrent sattelites. It seems worth it for the options that
it does provide.

: . . . . ontractors, subcontractors, etc., you are talking thousands of
people! At it's peak, I believe there were four or five hundred people
working on it at JPL alone. But then again... I could be wrong. But the
number has been calculated, I just don't remember some of these things
well.. . . [870 ]

Dr. Thrak : . . . . Wed, May 15, 8:46PM PDT (-0700 GMT). . . [870 ]
Critic, Galileo's problems have an interesting history. You might want to
look up Henry Cooper's article on the wondrous folding antenna in the New
Yorker, probably sometime around 1986-1988. Suffice to say, there was a time
when such a clever design was praised to the skies...

Frank : . . . . Wed, May 15, 8:48PM PDT (-0700 GMT). . . [871 ]
What is the upload data rate?

Magalhaes Planetary Scientist : . . . . Wed, May 15, 8:49PM PDT (-0700 GMT).
. . [872 ]
NASA Critic: You are correct, space scientist James Van Allen was indeed
arguing against the shuttle, but so were many other less prominent space
scientists. After the Challenger disaster, alternates to the shuttle became
a high priority. IN fact planetary probe missions started after Challenger,
no longer will be launched by Shuttle. Note for example the recent launch of
the NEAR (Near Earth Asteroid Rendezvous) mission. This will be true for all
future planetary probes.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:49PM PDT (-0700
GMT). . . [873 ]
Frank, sorry, I've got no clue. Maybe Steve knows...

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:50PM PDT (-0700
GMT). . . [874 ]
critic: you should use "you guys" and "20 years ago" in the same sentence.
None of us here were making policy decisions for NASA 20 or 30 years ago. It
takes a long time from planning to implementation, and decisions are always
easy to criticize in hindsight. In future, NASA plans to have more and
smaller missions, which should cut the design -] implementation time
considerably.

Billy Biggs, student : . . . . Wed, May 15, 8:50PM PDT (-0700 GMT). . . [875
]
Just before this ends, I'd like to say thanks to everybody who's still here
from NASA for putting this on and giving us an opportinuty to voice our own
questions about the Galileo mission. I know that for me, this session has
been amazingly informative and helpful. Thank you.

: . . . . Wed, May 15, 8:51PM PDT (-0700 GMT). . . [876 ]
How close will galileo come to Europa

Nasa : . . . . Wed, May 15, 8:51PM PDT (-0700 GMT). . . [877 ]
James Van Allens critisms were not in hinesight they were before the fact.

Webmaster@quest : . . . . Wed, May 15, 8:53PM PDT (-0700 GMT). . . [878 ]
WebChat will end in 10 minutes.

Nasa : . . . . Wed, May 15, 8:54PM PDT (-0700 GMT). . . [879 ]
How close did Galileo come to Europa on the missed encounter?

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:55PM PDT (-0700
GMT). . . [880 ]
Julio says Galileo will fly to within 1700 km of Europa.

: . . . . Wed, May 15, 8:55PM PDT (-0700 GMT). . . [881 ]
What will heppened to the galileo spacecraft at the end of her mission?
(Fall down in Jupiter, shouted to the outer space...)?

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:55PM
PDT (-0700 GMT). . . [882 ]
PERSONAL OPINION MODE ON: A principle rule of engineering economics is:
ignore sunk costs. The problem I have with the "dump the shuttle" camp is
that similar "critics" in the 70's argued that we needed to "dump the
Saturn" and create a system that provides "cheap access to space", namely,
the shuttle. I worry that around 2010 we may look back and kick ourselves
and say "damn, we had a decent, reusable, general purpose, manned spacecraft
and we dumped it". The "critics" of 2010 will be poking at us for doing it,
just like the "critics" of today poke at us for dumping the Saturn... OP-ED
MODE OFF (the above does not represent NASA or JPL opinion)

: . . . . Wed, May 15, 8:56PM PDT (-0700 GMT). . . [883 ]
What will heppened to the galileo spacecraft at the end of her mission?
(Fall down in Jupiter, shouted to the outer space...)?

: . . . . Wed, May 15, 8:56PM PDT (-0700 GMT). . . [884 ]
What is the closest Galileo will come to Europa, will it be closer then the
voyagers. Do you expect to be able to get good pictures of the ice surface
and confirm the ice is water

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 8:57PM PDT (-0700
GMT). . . [885 ]
: The orbiter will run out of fuel sometime after 2 years and will be unable
to maneuver (for orbit maintanence, antenna pointing, etc.)

: . . . . Wed, May 15, 8:57PM PDT (-0700 GMT). . . [886 ]
What will heppened to the galileo spacecraft at the end of her mission?
(Fall down in Jupiter, shouted to the outer space...)?

Webmaster@quest : . . . . Wed, May 15, 8:57PM PDT (-0700 GMT). . . [887 ]
WebChat will end in five minutes.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 8:58PM
PDT (-0700 GMT). . . [888 ]
I don't remember the upload rate for sure. Something makes me want to say 40
bits per sec. If you really care, drop me email and I'll ask and reply from
work tomorrow.

Nasa Critic : . . . . Wed, May 15, 8:58PM PDT (-0700 GMT). . . [889 ]
I appoligise if I have offended. Nasa has made some of the major
acomplishments of mankind. I just dont want to think to highly of
themselves.

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 8:59PM PDT (-0700
GMT). . . [890 ]
: Galileo will never have enough energy to escape from Jupiter, however, its
eventual fate (permanent orbit or atmospheric entry) is still unknown.

Dr. Thrak : . . . . Wed, May 15, 8:59PM PDT (-0700 GMT). . . [891 ]
nasa, of course Van Allen opposed it. The question is who supported it, yes?

hobbes Astronomer : . . . . Wed, May 15, 8:59PM PDT (-0700 GMT). . . [892 ]
Good bye everyone, this chat system is a quite nice feature. I found it to
be quite informative! Hope it comes around again.

: . . . . Wed, May 15, 8:59PM PDT (-0700 GMT). . . [893 ]
What will heppened to the galileo spacecraft at the end of her mission?
(Fall down in Jupiter, shouted to the outer space...)?

: . . . . Wed, May 15, 8:59PM PDT (-0700 GMT). . . [894 ]
Charlie Sobeck I was just wondering what your major was in College

Charlie Sobeck, Probe Engineering : . . . . Wed, May 15, 9:00PM PDT (-0700
GMT). . . [895 ]
EE

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 9:00PM
PDT (-0700 GMT). . . [896 ]
A thoughful critic is often our best friend...

frank : . . . . Wed, May 15, 9:00PM PDT (-0700 GMT). . . [897 ]
Thanks to all! 73

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 9:00PM PDT (-0700
GMT). . . [898 ]
thrak wants

Nasa Critic : . . . . Wed, May 15, 9:00PM PDT (-0700 GMT). . . [899 ]
NAsa neede to be flexible and do something very difficult. Admit when they
have erred.. I believe the shuttle was an error.

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 9:01PM PDT (-0700
GMT). . . [900 ]
to reach message number

Richard Gerber, Astrophysicist : . . . . Wed, May 15, 9:01PM PDT (-0700
GMT). . . [901 ]
900!

hobbes Astronomer : . . . . Wed, May 15, 9:01PM PDT (-0700 GMT). . . [902 ]
It would be great if they could make it stay in perminant orbit. So, some
years ahead of time, we could possibly recover the vehicle and see what went
wrong in the tape recorder and what damages the probe suffered. Or even to
see what the effects of radiation on the hull over a long period of time
does.

Webmaster@quest : . . . . Wed, May 15, 9:01PM PDT (-0700 GMT). . . [903 ]
WebChat will end in ONE minute.

Steve Collins Galileo Orbiter Engineering team : . . . . Wed, May 15, 9:01PM
PDT (-0700 GMT). . . [904 ]
To the moderators and Webbies who got this up and running: WELL DONE!

Magalhaes Planetary Scientist : . . . . Wed, May 15, 9:02PM PDT (-0700 GMT).
. . [905 ]
TO: . . . . Wed, May 15, 8:55PM PDT (-0700 GMT). YOUR QUESTION: What will
heppened to the galileo spacecraft at the end of her mission? (Fall down in
Jupiter, shouted to the outer space...)? ANSWER: The Galileo Orbiter is in a
very high orbit. It is forced to orbit very far above the cloud tops because
the radiation belts of Jupiter are so intense. If the Orbiter were to spend
even a few days, close to Jupiter the electronics would be severly damaged.
Therefore, the Orbiter will remain in orbit for eternity-- at the high
altitudes there is no atmospheric drag as there is say for satellites in low
Earth orbit. As far as the Galileo Probe, we need to speak of it in the past
tense. After its approximately one hour of radio transmissions, it continued
to descend into Jupiter (no solid surface to hit). Since temperature
increases as you go into Jupiter, the probe eventually vaporized a few hours
after atmospheric entry on Dec. 7. So now... the Probe no longer exists and
its atoms, which started as materials here on Earth, are no part of Jupiter.

Webmaster@quest : . . . . Wed, May 15, 9:03PM PDT (-0700 GMT). . . [906 ]
Good-bye. Thank you for participating. WebChat will be turned off NOW.